Abstract: A method of measuring motion power and resistance coefficient of a bicycle measures sensed data including at least one front projecting area of a bicycle ridden by a user, an air temperature value, an air pressure value, a traveling speed value, an acceleration value, a relative wind speed value, an inclination value and a total weight value to calculate an air resistance coefficient, a rolling friction coefficient of a bicycle tire, a force and a motion power applied to the bicycle by the user, so that the user may learn a better riding posture for different riding conditions and reduce the air resistance effectively by adjusting the riding posture, so as to reduce the consumed motion power. Through the installation of a display unit, the user may know about the data sensed by the sensor and the computation result of the processing unit anytime.

Abstract: The present invention discloses an intelligent signal processor of a vortex flowmeter, the signal processor mainly adopts a digital signal processor structure for processing a flow rate of a fluid. The signal processor uses two different algorithms, one primarily using a fast Fourier transformation (FFT) unit and an auto-correlation unit, and the other primarily using a fast Fourier transformation (FFT) unit and a digital software phase locked loop (SPLL) unit. As the flow rate varies with time, the two algorithms can track a vortex shedding frequency and reduce a vortex shedding frequency error. For maximum and minimum flow rates, a large difference of flow rates will not affect the precision of a measurement. If the flow rate ranges from 50 to 509 m3/hr, the precision is approximately equal to 0.59%˜0.35%, which has improved about 2˜3 times over the traditional processing method.

Abstract: A T-shape vortex shedder comprises a bluff body having a width W between upper and lower ends thereof and an extended plate having a length L in the fluid flow direction which is perpendicular to the bluff body. The bluff body and the extended plate form a T-shape vortex shedder with a T-shape cross section. When this T-shape vortex shedder is placed in a fluid motion within a circular pipe, the bluff body is located upstream of the fluid flow, and the extended plate is located downstream of the fluid flow, such that vortex shedding is produced at the upper and lower ends of the bluff body. The T-shape vortex shedder is characterized in that the L/W ratio is approximately 1.56.about.2.0, and the fluid flow produces steady vortex shedding when the Reynolds number of the fluid flow is approximately 2.4.times.10.sup.3 .about.3.2.times.10.sup.4.

Abstract: A vortex flowmeter which is capable of measuring flow speed and flow rate both rapidly and precisely. The vortex flowmeter is composed of a ring-type bluff body situated in a pipe as a vortex shedder. The ring is bevelled at an acute angle at the inner and outer edges of the ring and the vortex shedding frequencies generated by the ring can be transformed to flow speeds and flow rates. The geometrical parameters G/W and D/W of the ring are G/W=0.50 to 0.53 and D/W=5.03 to 10.63, where G denotes the gap width between the outer edge of the ring and the pipe wall, W denotes the width of the ring, and D denotes the mean diameter of the ring. After these vortex shedding frequencies are nondimensionalized, they show a relationship with the Reynolds Numbers. The optimal streamwise location for installation of a pressure sensor is in the region of X/W=2.25 to 2.84, where X denotes the axial distance from the leading surface of the ring frontal surface.

Abstract: An axisymmetric bluff body is proposed for a vortex flowmeter as the vortex shedder. It is found that vortex shedding frequencies measured can be nondimensionalized into a linear relation with the Reynolds number for area blockage ratios of circular disks up to 29.2%. Vortex shedding frequency can be clearly sensed by a pressure transducer installed on the pipe wall in the neighborhood of the maximum pressure fluctuation being measured. This suggests a feasible design that the sensor of a vortex flowmeter can be removed from the flow field or changed easily.