Abstract: An automated test cell and method for testing a gas turbine test engine is provided. The automated test cell includes a fuel subsystem, an engine lubrication subsystem, a test cell security subsystem, and a system controller. The system controller is in communication with the fuel subsystem, the engine lubrication subsystem, the test cell security subsystem, and a non-transitory memory storing instructions. The instructions when executed cause the system controller to: operate the test engine pursuant to a predetermined test cycle, including producing test data; control the engine lubrication subsystem to provide lubrication to the test engine pursuant to the predetermined test cycle; control the fuel subsystem to provide fuel to the test engine pursuant to the predetermined test cycle; control the test cell security subsystem to monitor an environment within the test cell; and report the test data.

Abstract: A vortex vibration wind tunnel test model system for a long-span bridge and a test method thereof is disclosed. In the test model system, the base is provided with a plurality of adjustment members, each of the adjustment members is provided with a cantilever rod, and all of the cantilever rods are cantilevered in the same direction; a beam body model is provided on a cantilevered end of all of the cantilever rods; a displacement measuring member is provided below the cantilever rod, and the horizontal distance between the displacement measuring member and the beam body model exceeds 2 times a width value of the beam body model, the displacement measuring member being away from the surface of the beam body model and the position of directly below the beam body model. Therefore, the state response data of the position of the cantilever rod can be collected in real time.

Abstract: A method of evaluating compliance of a component of an aircraft engine with flow requirements has: obtaining experimental data from experimental testing on a prototype of the component; obtaining a digitized model of a production model of the component, the digitized model including digitized apertures having geometrical data corresponding to that of apertures defined in the production model; computing a nominal mass flow rate through the digitized apertures using the geometrical data and flow parameters from the experimental data; correcting the nominal mass flow rate of the digitized model to obtain a computed mass flow rate of the production model; and assigning at least one parameter to the production model, the at least one parameter indicative of installation approval of the production model of the component for installation on the aircraft engine when the computed mass flow rate is determined to be within a prescribed range of the flow requirements.

Abstract: A passive bypass for an inlet to a supersonic or hypersonic air-breathing engine allows airflow in the inlet to exit through the cowling when the inlet supplies more airflow than the air-breathing engine demands. The air-breathing engine may be the only form of propulsion or a secondary form of propulsion to reach higher speeds. The passive bypass includes a plurality of lower channels in the cowling that are operatively coupled to the inlet diffuser at an inner surface of the cowling and swept forward towards the throat, a plenum in the cowling operatively coupled to the plurality of lower openings and a plurality of upper channels in the cowling that are operatively coupled to the plenum and swept back away from the throat to an outer surface of the cowling. A serpentine path through the plurality of lower openings, the plenum and the plurality of upper openings allows airflow in the inlet to exit through the cowling when the inlet supplies more airflow than the air-breathing engine demands.

Abstract: An assembly includes an enclosure including first and second regions spaced apart along a first direction, and a plurality of spaced apart acoustic baffles arranged along a second direction different from the first direction and disposed in the enclosure between the first and second regions. The plurality of spaced apart acoustic baffles includes adjacent first and second acoustic baffles. Each of the first and second acoustic baffles include an acoustically absorptive layer disposed on a sheet having a specific airflow resistance greater than 200 MKS Rayl. The first and second acoustic baffles define a channel therebetween. At least a portion of the channel extends along a longitudinal direction making an oblique angle with the first direction.

Abstract: A variable 3D CD nozzle includes: a flexible body defining a flow path having an inlet extending through a narrowed throat to an expanded outlet, wherein the flexible body comprises a plurality of flexible members movably interconnected together; and at least one means for changing a shape of the flexible body to change a dimension or location of the throat plane relative to at least one of the inlet plane or outlet plane. A method of changing airflow in a nozzle includes operating at least one means for changing the shape of the flexible nozzle body to change the dimension or the location of the throat plane. A method of testing an object includes placing a test object in the test region of the test cell and passing a test gas from the outlet opening of the nozzle onto the test object.

Abstract: A method of determining vapor pressure of a fluid is provided. The method comprises the step of providing a meter having meter electronics, wherein the meter comprises at least one of a flowmeter and a densitometer. A process fluid is flowed through the meter. A low-pressure location associated with the meter is provided. The pressure of the process fluid is adjusted until flashing is detectable at the low-pressure location. The true vapor pressure of the process fluid is calculated at an instant where flashing is detected.

Abstract: A multi-loop natural circulation experimental device under six-degree-of-freedom motion conditions and a method therefor are provided. The device includes: a six-degree-of-freedom motion simulation platform; a multi-loop main circulation loop including a serpentine pre-heater, an experimental section, two sleeve-type condensers, and a pressurized circulating pump, a voltage stabilizer and related equipment; and a cooling water system including a sleeve condenser, a plate heat exchanger, a cooling tower, a cooling fan, a cooling water tank and related equipment; and an electric heating system including a DC power supply, a low voltage power controller and a transformer. The present invention also provides an experimental method of the device.

Abstract: A system includes a surface, an actuator, and processing circuitry. The surface includes one or more non-actuating zones and one or more actuatable zones. The actuator is configured to a flow property of a fluid that flows over the one or more actuatable zones of the surface. The processing circuitry is configured to obtain a value of a parameter of the fluid that flows over the surface, and operate the actuator to adjust the flow property of the fluid that flows over the one or more actuatable zones based on the value of the parameter of the fluid.

Abstract: A position limiting protection device for a test platform of a triaxial air-bearing turntable and its working method are provided. The triaxial air-bearing turntable is installed on a support frame and includes an air bearing support seat and an air bearing hemisphere. A test platform is placed on an adapter plate, which is placed above the air bearing hemisphere. The position limiting protection device includes three top rods and three annular parts, which are sequentially spaced to form a position limiting ring, the position limiting ring is located below the adapter plate and surrounds the air bearing hemisphere. The position limiting ring is spaced at a certain distance from the air bearing hemisphere, each annular part is fixed on a support frame, and the top rods are controlled to rise or fall to limit the movement of the test platform.

Abstract: Systems and methods for modeling electric vehicle towing are disclosed herein. An example method includes determining that a trailer is connected to a vehicle, generating a surface mapping of the trailer based on output of a sensor assembly of the vehicle, predicting a drag coefficient of the trailer based on the surface mapping, estimating a drag force based on the drag coefficient and the surface mapping, calculating an estimated range for the vehicle based on the drag force, and displaying the estimated range on a human machine interface of the vehicle.

Abstract: A portable tracer fluid injection system. The system has a vapor cloud generator which vaporizes a vapor cloud generating liquid. The vapor cloud generator is uses a sub-ohm resistive heater to vaporize small volumes of the vapor cloud generating liquid, allowing for a relatively small tracer fluid injection system. This system has the benefit of being able to target specific regions of a test object within a wind tunnel and being usable for different positions within the test section of a wind tunnel.

Abstract: An instrumented wind tunnel. The wind tunnel receives a test subject which can be a model of an object to be tested with dynamic airflow. The test subject is fitted with at least one sensor to deliver data to a chassis, which in turn uses a network having at least 10 Gb/s capability to deliver the data to a RAM cache. The RAM cache can push the data to multiple viewers for real time monitoring of wind tunnel tests. The operator can then make live adjustments of the test conditions.

Abstract: A busway joint for coupling two segments of an electrical distribution busway to each other comprising, a busway joint including a plurality of fins, a central body connecting each of the plurality of fins, and a bolt within the central body, wherein the bolt includes a cavity housing a sensor lead and an epoxy potting.

Abstract: There is a need to develop new internal balance structures that allow for measurements of aerodynamic interference forces (e.g., powered descent forces) in addition to aerodynamic loads. For example, supersonic retropropulsion (SRP) is a technique involving thrusters in opposition to the oncoming airflow to decelerate an aircraft vehicle while traveling at supersonic speeds. SRP has been identified as a key entry, descent, and landing technology for future Mars missions and for reuse of rocket boosters on Earth. Because of the propellant and oxidizer mass required for the thrusters, currently proposed SRP configurations require a significant increase in performance and efficiency before considered an effective solution. The challenge is that this procedure may cause the air around the spacecraft to become unstable.

Abstract: Disclosed herein is a technique of configuring flexible photovoltaic tracker systems with high damping and low angle stow positions. Under dynamic environmental loads implementing a high amount of damping (e.g., greater than 25% of critical damping, greater than 50% of critical damping) or a very high amount of damping (e.g., 100% or greater of critical damping, infinite damping) enables the flexible tracker system to prevent problematic aeroelastic behaviors while positioned in a low stow angle. The disclosed technique is further applied to a prototyping process during wind tunnel testing.

Abstract: A wind tunnel for a motor vehicle, with a fan, a test section, through which an air stream generated by the fan can flow, a recording device for recording different motor vehicles within the test section, and a testing device for determining aerodynamic characteristics of the motor vehicle. The wind tunnel also includes an optical sensing device for sensing an outer contour of the motor vehicle recorded by the recording device, an evaluating unit and a linking unit. The evaluating unit determines a vehicle configuration from the outer contour of the motor vehicle sensed by the optical sensing device. The linking unit links the vehicle configuration of the motor vehicle determined by the evaluating unit with the test results determined by the testing device.

Abstract: A ramjet including: a combustion area having an air inlet and an exhaust outlet; and a fuel cell in fluid communication with the air inlet and a fuel supply of the ramjet, wherein the fuel cell is in thermal communication with the combustion area.

Abstract: The disclosed technology relates to a field serviceable pressure scanner suitable for high-pressure sensing applications and replacement of large pressure transmitter panels. The pressure scanner includes a housing having a mounting plate comprising a plurality of through-hole bores extending from a front to back side for mating with corresponding transducer ports of the pressure sensors, and a plurality of input ports disposed on the front side of the mounting plate and in communication with the corresponding plurality of through-hole bores. The pressure scanner assembly includes two or more field-replaceable (swappable) pressure sensors seal mounted to the back side of the mounting plate, each pressure sensor comprising one or more sensor ports, each of the one or more sensor port in communication with corresponding through-hole bores in the mounting plate, and a multi-channel data acquisition system configured to receive pressure signals from the two or more field-replaceable pressure sensors.

Abstract: Disclosed are a system and methods for calibrating wall shear stress sensors. The system includes an oscillating plate coupled to an actuator and mounted on a rolling elements, and one or more sensors coupled to a height adjusting device. The system can further comprise a height control rod coupled to a height control base and a sensor holder configured to house the one or more sensors and supported on a connector, the connector configured to be rotatably disposed about the height control rod. The system can be calibrated by causing the actuator to oscillate the oscillating plate at a frequency, sensing, using the one or more sensors, shear stress at a wall, the shear stress at the wall being associated with a velocity field, and determining a theoretical wall shear stress based on fluid properties, the frequency, and the height of the one or more sensors above the oscillating plate.

Abstract: A fan logic evaluation device and method thereof for improving the logic evaluation of a fan. Specifically, a fan logic evaluation device is provided by first installing a fan, which corresponds to a set of parameters, in a wind tunnel device. A computer then performs a logic evaluation to convert the set of parameters into an evaluated pressure-flow curve and a measured pressure-flow curve by measuring the fan's operating conditions with the wind tunnel device. The computer further performs a logic modification to correct the logic evaluation to obtain a logic evaluation modification. The logic evaluation is then replaced by the logic evaluation modification. Finally, the above process is repeated with the same fan or a different fan.

Abstract: A system for delivering a therapeutic amount of nitric oxide can include a reservoir containing a nitrogen dioxide source. A heating element can be configured to heat the reservoir, causing nitrogen dioxide vapor to exit the reservoir through a restrictor into a conduit. The nitrogen dioxide vapor can mix with gas from a gas supply, which can then flow to a cartridge that includes a surface-activated material saturated with an aqueous solution of a reducing agent. The cartridge can convert the nitrogen dioxide into nitric oxide.

Abstract: An assembly is provided for an aircraft propulsion system. This aircraft propulsion system assembly includes an aircraft propulsion system component with a leading edge. The aircraft propulsion system assembly also includes artificial ice attached to the aircraft propulsion system component. The artificial ice at least partially covers and extends longitudinally along the leading edge.

Abstract: Embodiments of the present disclosure provide a diffusion muffling device, a diffusion resonance muffling device, a full-frequency diffusion muffling device, a muffling system for a ventilation channel, and a muffling method using the same, which include a plurality of diffusion muffling units disposed in the ventilation extension direction of the ventilation channel, wherein the plurality of diffusion muffling units are arranged in parallel in a direction with a predetermined angle between the direction and the ventilation extension direction of the ventilation channel, and a muffling passage is formed between each two adjacent diffusion muffling units, wherein each of the diffusion muffling units includes at least one diffuser, and each diffuser includes a plurality of convex portions so that sound waves entering the muffling passage are reflected multiple times in the muffling passage by the plurality of convex portions and then sound is attenuated.

Abstract: A system may include at least one processor. The at least one processor may be configured to: obtain air traffic data associated with at least one air traffic target; based at least on the air traffic data, determine at least one estimated wake turbulence trail for each of the at least one air traffic target; and at least one of: (a) generate at least one display image based at least on the at least one estimated wake turbulence trail and output the at least one display image to at least one display for presentation to a user, each of the at least one display image including at least one wake turbulence trail indicator, the at least one wake turbulence trail indicator generated based at least on the at least one estimated wake turbulence trail; or (b) operate the aircraft to avoid the at least one estimated wake turbulence trail.

Abstract: A method includes simultaneously controlling and sensing aerodynamic loading of a membrane wing using a capacitance of the membrane, the membrane wing stretching under aerodynamic load, leading to thinning of a membrane thickness and increased capacitance, and using knowledge of the membrane's elastic and dielectric material properties to determine an amount of steady aerodynamic lift being generated.

Abstract: A rotor blade of a rotor of a wind turbine, and to an associated wind turbine, and to a method for optimizing a wind turbine. Prior to being mounted on the wind turbine, the rotor blade is split at a parting point into an inner blade section and an outer blade section, wherein a longitudinal direction of the rotor blade is defined from the root section to the blade tip, wherein the rotor blade has at least one swirl element, wherein the swirl element has an extent in the longitudinal direction of the rotor blade, wherein a distance between a start, facing toward the root section, and an end, facing toward the rotor blade tip, of the swirl element in the longitudinal direction is referred to as total length, and wherein a distance between the parting point and the outer end of the swirl element is referred to as outer length, wherein a ratio of outer length to total length is less than 0.25.

Abstract: A parameter similarity method for test simulation conditions of an aerodynamic heating environment is disclosed. With respect to the requirement that the adiabatic wall enthalpy and the cold-wall heat flux are equal in the simulation test of the aerodynamic heating environment, a method that can ensure the similarity of ground test parameters and flight parameters without the equal adiabatic wall enthalpy is proposed, and solves the problems of relying on the equal adiabatic wall enthalpy and making it difficult to accurately simulate the real aerodynamic heating environment in the current test simulation method, and provides guarantee for heat transfer and ablation test research of thermal protection/insulation material under the high temperature aerodynamic heating environment. The test conditions are not affected by the value of the adiabatic wall enthalpy. According to the method, most test devices can simulate the aerodynamic heating environment with high enthalpy.

Abstract: Disclosed herein is a technique of configuring flexible photovoltaic tracker systems with high damping and low angle stow positions. Under dynamic environmental loads implementing a high amount of damping (e.g., greater than 25% of critical damping, greater than 50% of critical damping) or a very high amount of damping (e.g., 100% or greater of critical damping, infinite damping) enables the flexible tracker system to prevent problematic aeroelastic behaviors while positioned in a low stow angle. The disclosed technique is further applied to a prototyping process during wind tunnel testing.

Abstract: A free fall simulator comprising: a wind tunnel system; a flight chamber connected to the wind tunnel allowing for a continuous flow of circulating air, and a cooling system for cooling of the air circulating in the wind tunnel system, wherein the cooling system comprises: an air inlet sucking in a part of the air circulating in the wind tunnel system; at least one heat exchanger comprising a coolant; and at least one air outlet adapted such that the cooled air leaves the cooling system through the at least one air outlet. The cooling system further comprises: a closed pressure chamber comprising a cooling area having pressure higher than atmospheric pressure, and at least one auxiliary fan. The at least one heat exchanger is located inside of the closed pressure chamber so that the cooling of the circulating air takes place in the cooling area.

Abstract: A tuned mass absorber assembly comprises a mass structure, and a flexure system comprising first and second flexure sections (e.g., cross bar flexures) supported by, and extending in opposing directions from, the mass structure. The flexure system can comprise flexure section mounts situated at distal ends of the first and second flexure sections, respectively, and that are operable to mount the tuned mass absorber assembly to a structure subject to induced vibrations therein. A mass of the mass structure and a stiffness of the flexure system can be tuned to attenuate vibrations at a specific input frequency generated in response to induced vibrations of the structure. A system can comprise a vibration isolator attached to a chassis (e.g., of an airplane), and supporting a payload (sensors(s)) and isolating the payload from vibrations. A tuned mass absorber assembly can be mounted to the vibration isolator for attenuating vibrations at a specific input frequency that may affect the payload.

Abstract: A wind tunnel sting comprising a support member and a wind tunnel sting damper. The support member having a first support-member end configured for coupling with a wind tunnel, and a second support-member end configured for coupling with a balance. The wind tunnel sting damper having a reactive member, and a viscoelastic member disposed between the reactive member and the support member wherein, the reactive member is sized relative to the support member so as to radially compress the viscoelastic member against the support member.

Abstract: A balance protection system for a wind tunnel test system that includes a balance component, a model component connected to the balance component and a sting component connected to the balance component is disclosed. The balance protection system includes a first set of features on the model component that mate with a second of features on to the sting component. The clearances between the first and second set of features determine an amount of allowed movement of the model with respect to the balance. Actuators can be used to actively adjust the amount of clearance and respective allowed movement of the model with respect to the balance. Limiting movement of the model with respect to the balance protects the balance from damage caused by excessive forces applied to the model.

Abstract: A sensing mechanism of a two-dimensional airfoil model, which includes pressure sensor groups, multiple first tubes, the second tube, and a cavity. The pressure sensor groups are vertically fixed to mounting holes in the surface of the two-dimensional airfoil model. The pressure measurement surface of each pressure sensor is vertical to the surface of the two-dimensional airfoil model. Multiple mounting holes are opened in and vertical to the surface of the two-dimensional airfoil model. The cavity is fixed to the interior of the two-dimensional airfoil model. The reference pressure end of each pressure sensor is connected to the cavity through the first tube, the multiple pressure sensors of the pressure sensor groups are in one-to-one correspondence with the multiple first tubes. The cavity is connected with the first end of the second tube. The second end of the second tube is located in the air outside the two-dimensional airfoil model.

Abstract: A drivetrain for an aircraft includes an engine, a driveshaft receiving rotational energy from the engine and a gearbox including a planetary gear system receiving rotational energy from the driveshaft. The planetary gear system includes a sun gear, planet gears, a ring gear and an integral carrier forming flexured carrier posts. Each flexured carrier post supports a respective one of the planet gears and has a fixed proximal end and a cantilevered distal end. The planetary gear system includes flexured roller races, each having a fixed end and a cantilevered end. The fixed end of each flexured roller race is coupled to the cantilevered distal end of a respective flexured carrier post. The planet gears engage with the flexured roller races to rotate about the flexured carrier posts. The cantilevered ends of the flexured roller races experience cantilevered motion to absorb loads from the planet gears.

Abstract: A test bench, in particular a convertible wind channel balance, including a lifting frame for lifting at least one wheel belt unit, wherein the wheel belt unit has at least one belt which is looped around at least two rollers, a weighing platform, which is mounted so as to be relatively movable in relation to a test bench frame, at least one force sensing member arranged between the weighing platform and the test bench frame in order to sense forces between the weighing platform and the test bench frame, wherein at least one self-centering docking member is provided between an auxiliary frame and the weighing platform.

Abstract: A wind tunnel device is provided herein that enables the wind tunnel to transform between two modes of operation and/or to refresh/recondition air within the tunnel. The wind tunnel device may provide selective diversion of airflow within the wind tunnel. The diversion of airflow may enable the wind tunnel device to include a multi-configurable wind tunnel that can be operated as either an open-return wind tunnel or a closed-return wind tunnel. Additionally, or alternatively, the diversion of airflow may enable the wind tunnel device to recondition air within a closed-return wind tunnel.

Abstract: The present disclosure provides methods and systems for propeller balancing of an aircraft comprising a propeller. Acceleration data is obtained from an acceleration sensor coupled to the aircraft. The acceleration data is filtered using a filter to obtain propeller-specific vibration data, the filter defining a range of acceptable frequencies associated with a frequency of rotation of the propeller. The propeller-specific vibration data is compared to trend data associated with the propeller. When the propeller-specific vibration data differs from the trend data beyond a predetermined threshold, an alert indicative of a balancing need for the propeller is issued.

Abstract: The invention relates to a wind generation means (1) comprising at least one wind generation wall (1?) comprising a plurality of wind generation units (11) provided next to each other along at least a first and a second directions so as to form the at least one wind generation wall (1?), wherein each wind generation unit (11) of said plurality of wind generation units comprises at least two ventilation units (111), each ventilation unit within the wind generation unit being individually controlled, characterized in that each wind generation unit (11) of said plurality of wind generation units comprises at least one control unit adapted to control said ventilation units (111) individually, so as to generate an arbitrary wind profile both in space and in time in an air flow path and so as to vary a generated wind physical property of said each wind generation unit along said at least first and second directions, and in that said plurality of wind generation units (11) are detachably attached to each other so th

Abstract: A method, comprises: receiving measured air pressure data from each air data probe on a vehicle; receiving a first set of data from at least one sensor system on the vehicle; determining predicted noise levels for each air data probe using a noise modelling system and the received first set of data; determining a transmission loss for each air data probe; determining if any air data probe is faulty by determining if an transmission loss of any of the air data probes is greater than a first threshold value, where an air data probe is deemed faulty if its transmission loss is greater than the first threshold value; and if the transmission loss of any of the air data probes is greater than the first threshold value, then generating a signal to indicated that at least one air data probe is faulty.

Abstract: The invention relates to a device for simulating the centrifugal acceleration applied to at least one aeronautical turbomachine rotor blade. This device is notable in that it comprises at least one rotor disc (2) comprising a rim in which there are formed a plurality of pockets (23) delimited by two lateral teeth (24) and at least one simulation test (3) which comprises a screw (32), a spacer (33) and a dummy blade (31), in the dummy blade comprises a bore (347), which is tapped over at least part of its length and in that the dummy blade, the screw and the spacer are configured and arranged in such a way that when the screw is screwed into the tapped bore, the root (35) of the dummy blade is engaged in the pocket in the disc, the screw comes into abutment against the spacer and presses same against the two lateral teeth situated one on each side of the pocket in the rotor disc and that this causes the dummy blade to move towards the outside of the disc.

Abstract: The present invention discloses a tunnel deformation monitoring system, which includes: a laser distance measuring instrument, disposed on a side wall of a maximum horizontal width of a tunnel, and configured to measure the width of a cross section of the tunnel; a surveillance camera, disposed on the laser distance measuring instrument, and configured to view the scene of the tunnel; a control and transmission device, configured to receive a control command and control the laser distance measuring instrument and the surveillance camera, and receive monitoring data of the laser distance measuring instrument and video data acquired by the surveillance camera; and a remote control terminal, configured to send a control command to the control and transmission device, receive the monitoring data and the video data, and analyze and display the monitoring data and the video data.

Abstract: An experimental setup for three-degree-of-freedom large-amplitude free vibration in a wind tunnel test. The setup includes a rigid test model, rigid circular rods, rigid lifting arms, arc blocks with grooves, lightweight high-strength thin strings, linear tensile springs, fixed pulleys, and bearings. Large-amplitude three-degree-of-freedom free vibrations of test models can be adapted by the vertical deformation of the springs without any tilt. The possible nonlinear mechanical stiffness due to vertical spring tilt and lateral spring deflection are excluded. It is convenient to install the test model and adjust the initial angle of attack in the new experimental setup. The linear stiffness property and hence constant vibration frequency can be ensured for very large-amplitude vibrations due to the eliminations of spring deflection and tilt.

Abstract: A monitoring device includes a cavity assembly with a plurality of cavities. Openings of the plurality of cavities are distributed about a flow-facing surface of the cavity assembly. A gas pressure sensor is disposed within each of the cavities, and is configured to measure an absolute pressure of a gas flow which flows past the monitoring device. Gas pressure measurements from the pressure sensors may be used to determine a flow speed and a flow direction of the gas flow. More specifically, a mapping may be used to map the logarithm of the difference between the maximum and minimum pressures to a flow speed. Further, a lookup table may be used to map a pattern of pressure measurements to a flow direction.

Abstract: A large-amplitude vertical-torsional coupled free vibration testing device for wind tunnel test. The large-amplitude vertical-torsional coupled free vibration device for wind tunnel test includes rigid deck model, lightweight rigid rods, lightweight rigid circular aluminium hubs, the first thin strings, linear tensile vertical springs, and the second lightweight strings. Large-amplitude vertical-torsional coupled free vibrations of rigid deck models can be realized by using this device, in which the springs vertically deform without any tilt. In the traditional free vibration device, the spring may obviously tilt, and the linear torsional stiffness cannot be ensured. The device can be conveniently installed and the initial angle of attack can be easily adjusted. The extreme low and stable mechanical damping ratio required for large-amplitude vibrations can be readily guaranteed, owing to the invocation of the negligible rolling friction between the thin strings and the hub.

Abstract: An experimental setup for bridge deck large-amplitude vertical-torsional coupled free vibration in wind tunnel test, which belongs to the technical field of wind tunnel test apparatus. The experimental setup includes the rigid model, the rigid circular rods, the lightweight rigid circular sprockets, the chains, the linear tensile vertical springs, the bearings, the sliders, and the guides. For the new setup, large-amplitude vertical-torsional coupled free vibration of a rigid deck model that failed in conventional testing device can be adapted by the vertical deformation of the springs without any lateral tilt. As a result, the possible nonlinear mechanical stiffness due to the springs tilt in conventional testing device is excluded. In addition, owing to the low rolling friction and damping between the sprockets and the chains, the mechanical damping ratio of the system are quite low and stable for very large-amplitude vibrations.

Abstract: A turbulence generation system includes a vane assembly to direct airflow from a nozzle. The vane assembly includes at least two vertically oriented nozzle contraction vanes, a pair of vertically oriented nozzle exit vanes, and at least one horizontally oriented vane. The nozzle contraction vanes are located within the nozzle upstream of a nozzle air outlet. Each nozzle contraction vane rotationally moves independent of the other nozzle contraction vane to generate airflow pressure loss, turbulence and/or flow vectoring. The nozzle exit vanes are downstream of the air outlet and rotationally move to generate higher angles of dynamic yaw or a quick yaw input. The nozzle exit vanes are positioned laterally inward from first and second sidewalls of the nozzle. The horizontally oriented vane is positioned downstream of nozzle contraction vanes and upstream of the nozzle exit vanes and rotationally moves to generate up-wash or downwash.

Abstract: In an embodiment, a test section comprises at least one surface defining an at least partially enclosed space. The at least partially enclosed space defines an airflow path for air to flow. The test section also comprises a nozzle disposed in the at least partially enclosed space. The nozzle is configured to spray an agricultural spray and is positioned to emit the agricultural spray such that at least a section of the agricultural spray exhibits a non-parallel angle relative to the airflow path defined by the at least partially enclosed space. The test section further comprises at least one stimulus source positioned to illuminate at least a portion of the agricultural spray adjacent to the nozzle. Additionally, the test section comprises at least one detector positioned to image at least the portion of the agricultural spray adjacent to the nozzle.

Abstract: A system for determining rim shape includes a memory and a processor in communication with the memory. The processor is configured to receive one or more specifications for a rim. The processor is also configured to determine a rim depth for the rim based at least in part on the one or more specifications and a pareto front of rim shapes. The processor is also configured to determine a curvature control ratio and an endpoint tangency angle for the rim based at least in part on the rim depth. The processor is further configured to generate a rim shape for the rim based at least in part on the rim depth, the curvature control ratio, and the endpoint tangency angle.

Abstract: A wind tunnel device is provided herein that enables the wind tunnel to transform between two modes of operation and/or to refresh/recondition air within the tunnel. The wind tunnel device may provide selective diversion of airflow within the wind tunnel. The diversion of airflow may enable the wind tunnel device to include a multi-configurable wind tunnel that can be operated as either an open-return wind tunnel or a closed-return wind tunnel. Additionally, or alternatively, the diversion of airflow may enable the wind tunnel device to recondition air within a closed-return wind tunnel.