Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for fluid blob tracking. One of the methods includes identifying, by a computer system, a connected fluid phase region in a flow simulation. The method includes tracking, by the computer system, the connected fluid phase region over a first timeframe and a second timeframe. The method also includes determining, by the computer system, movement of the connected fluid phase region from the first timeframe to the second timeframe based on the tracking.

Abstract: A computer-implemented method for simulating flow and acoustic interaction of a fluid with a porous medium includes simulating activity of a fluid in a first volume adjoining a second volume, the activity of the fluid in the first volume being simulated so as to model movement of elements within the first volume and using a first model having a first set of parameters, simulating activity of the fluid in the second volume occupied by the porous medium, the activity in the second volume being simulated so as to model movement of elements within the second volume and using a second model having a second set of parameters, and simulating movement of elements between the first volume and the second volume at an interface between the first volume and the second volume.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for processing data in a data processing system to identify candidate modifications to physical features of a mechanical device. One of the methods includes converting a representation of the mechanical device into a representation of surface elements. The method includes that based on the representation of the surface elements, computing an effect to evaluation criteria of each of a design variable. The method includes converting the design variables and the computed effect into component vectors. The method includes computing a composite design vector for the evaluation criteria using the component vectors, with the composite design vector comprising a combination of design variable settings to improve the evaluation criteria, and specifying a vector in a design variable space. The method also includes generating a physical modification specification for the mechanical device based on the composite design vector.

Abstract: A method comprising: simulating, in a lattice velocity set, movement of particles in a volume of fluid, with the movement causing collision among the particles; based on the simulated movement, determining relative particle velocity of a particle at a particular location within the volume, with the relative particle velocity being a difference between (i) an absolute velocity of the particle at the particular location within the volume and measured under zero flow of the volume, and (ii) a mean velocity of one or more of the particles at the particular location within the volume; and determining, based on the relative particle velocity, a non-equilibrium post-collide distribution function of a specified order that is representative of the collision.

Abstract: A method for simulating a fluid flow that includes a laminar to turbulent boundary layer transition on a computer, the method comprising: for one or more locations on or near a boundary surface: performing a first calculation where a local boundary layer is taken to be a laminar boundary layer; performing a second calculation where the local boundary layer is taken to be a turbulent boundary layer; comparing a result from the first calculation to a result from the second calculation; and based on the comparing, selecting the result of the first calculation or the result of the second calculation; and inputting the selected result for the one or more locations into a simulation of activity of a fluid in a volume comprising the boundary surface.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for fluid blob tracking. One of the methods includes identifying, by a computer system, a connected fluid phase region in a flow simulation. The method includes tracking, by the computer system, the connected fluid phase region over a first timeframe and a second timeframe. The method also includes determining, by the computer system, movement of the connected fluid phase region from the first timeframe to the second timeframe based on the tracking.

Abstract: A fluid flow is simulated by causing a computer to perform operations on data stored in the memory to compute at least one eddy of a fluid flow at a first scale and perform operations to compute at least one eddy of the fluid flow at both the first scale and a second scale. The second scale is a finer scale than the first scale, and the computation of the at least one eddy of the fluid flow at the second scale is constrained by results of the computation of the at least one eddy of the fluid flow at the first scale.

Abstract: A computer-implemented method for simulating flow and acoustic interaction of a fluid with a porous medium includes simulating activity of a fluid in a first volume adjoining a second occupied by a porous medium, the activity of the fluid in the first volume being simulated so as to model movement of elements within the first volume and using a first model having a first set of parameters, simulating activity of the fluid in the second volume occupied by the porous medium, the activity in the second volume being simulated so as to model movement of elements within the second volume and using a second model having a second set of parameters and differing from the first model in a way that accounts for flow and acoustic properties of the porous medium, and simulating movement of elements between the first volume and the second volume at an interface between the first volume and the second volume.

Abstract: A fluid flow is simulated by causing a computer to perform operations on data stored in the memory to compute at least one eddy of a fluid flow at a first scale and perform operations to compute at least one eddy of the fluid flow at both the first scale and a second scale. The second scale is a finer scale than the first scale, and the computation of the at least one eddy of the fluid flow at the second scale is constrained by results of the computation of the at least one eddy of the fluid flow at the first scale.

Abstract: This description relates to computer simulation of physical processes, such as computer simulation of multi-species flow through porous media including the determination/estimation of relative permeabilities for the multi-species flow through the porous media.

Abstract: A computer-implemented method for simulating fluid flow using a lattice Boltzmann (LB) approach that includes assigning values for the wall shear stress on a per-facet (e.g., per-surfel) basis based on whether the fluid flow is laminar or turbulent is described herein.

Abstract: A fluid flow is simulated by causing a computer to perform operations on data stored in the memory to compute at least one eddy of a fluid flow at a first scale and perform operations to compute at least one eddy of the fluid flow at both the first scale and a second scale. The second scale is a finer scale than the first scale, and the computation of the at least one eddy of the fluid flow at the second scale is constrained by results of the computation of the at least one eddy of the fluid flow at the first scale.

Abstract: Simulating a physical process includes storing, in a computer-accessible memory, state vectors for voxels, where the state vectors correspond to a model and include entries that correspond to particular momentum states of possible momentum states at a voxel. Interaction operations are performed on the state vectors. The interaction operations model interactions between elements of different momentum states according to the model. Move operations performed on the state vectors reflect movement of elements to new voxels according to the model. The model is adapted to simulate a high-Knudsen number flow that has a Knudsen number greater than 0.1.

Abstract: Simulating a physical process includes storing, in a computer-accessible memory, state vectors for voxels, where the state vectors correspond to a model and include entries that correspond to particular momentum states of possible momentum states at a voxel. Interaction operations are performed on the state vectors. The interaction operations model interactions between elements of different momentum states according to the model. Move operations performed on the state vectors reflect movement of elements to new voxels according to the model. The model is adapted to simulate a high-Knudsen number flow that has a Knudsen number greater than 0.1.

Abstract: Simulating a physical process includes storing, in a computer-accessible memory, state vectors for voxels, where the state vectors correspond to a model and include entries that correspond to particular momentum states of possible momentum states at a voxel. Interaction operations are performed on the state vectors. The interaction operations model interactions between elements of different momentum states according to the model. Move operations performed on the state vectors reflect movement of elements to new voxels according to the model. The model is adapted to simulate a high-Knudsen number flow that has a Knudsen number greater than 0.1.

Abstract: A physical process is simulated by storing in a memory state vectors for voxels. The state vectors include entries that correspond to particular momentum states of possible momentum states at a voxel. Interaction operations are performed on the state vectors. The interaction operations model interactions between elements of different momentum states. For a particular state vector, the interaction operations include calculating a desired distribution of elements for a voxel represented by the particular state vector, the desired distribution including a number of entries corresponding to the number of entries in the particular state vector.When one or more entries of the desired distribution has an out-of-range value, the desired distribution is modified to correct the out-of-range value. The state vector then is updated to correspond to the modified desired distribution. Finally, move operations are performed on the state vectors to reflect movement of elements to new voxels.

Abstract: A physical process is simulated by storing in a memory state vectors for voxels. The state vectors include entries that correspond to particular momentum states of possible momentum states at a voxel. Iinteraction operations are performed on the state vectors. The interaction operations model interactions between elements of different momentum states. For a particular state vector, the interaction operations include performing energy-exchanging interaction operations that model interactions between elements of different momentum states that represent different energy levels. A rate factor for the voxel represented by the particular state vector affects a degree to which energy-exchanging interaction operations cause a transfer of elements from states representing lower energy levels to states representing higher energy levels, rather than from states representing higher energy levels to states representing lower energy levels.

Abstract: A physical process is simulated by storing in a memory state vectors for voxels and a representation of at least one surface. The state vectors include entries that correspond to particular momentum states of set of possible momentum states at a voxel. Interaction operations are performed on the state vectors to model interactions between elements of different momentum states. In addition, surface interaction operations are performed on the representation of the surface. The surface interaction operations model interactions between the surface and elements of at least one voxel near the surface. The elements have a tangential momentum relative to the surface, and the surface interaction operations retain at least a portion of the tangential momentum of the elements. The portion of tangential momentum retained corresponds to a friction parameter. The friction parameter is varied based on changes in pressure near the surface.

Abstract: To simulate physical processes, state vectors for each of multiple voxels are stored in a memory along with a representation for each of multiple facets that are sized and oriented independently of the size and orientation of the voxels and, in combination, represent one or more surfaces. Each state vector includes multiple entries, each of which corresponds to a number of elements at a particular momentum state of multiple possible momentum states at a voxel. Interaction operations that model interactions between elements of different momentum states are performed on the state vectors, and surface interaction operations that model interactions between a facet and elements at one or more voxels near the facet are performed on the representations of facets. Finally, move operations that reflect movement of elements to new voxels are performed on the state vectors.

Abstract: A computer implemented method for simulating a physical process. The method includes storing in a memory a state vector for each of a number of voxels. Each state vector includes a plurality of integers, each of which corresponds to a particular momentum state of a number of possible momentum states at a voxel and represents the number of elements having the particular momentum state. Each integer has more than two possible values. The method also includes performing interaction operations that model interactions between elements of different momentum states and include interaction rules that operate on a subset of the integers of a state vector. The interaction rules comprise a collision operator that transfers between integers representing a first set of momentum states and integers representing a second set of momentum states a number of elements that is determined based on the number of elements in the first and second sets of momentum states.