Feng Qiu, Ye Zhao, Zhe Fan, Xiaomin Wei, Haik Lorenz, Jianning Wang, Suzanne Yoakum-Stover, Arie Kaufman, Klaus Mueller Center for Visual Computing and Department of Computer Science, Stony Brook University GPU Accelerated Dispersion Simulation for Urban Security Overview Simulating and visualizing the propagation of dispersive contaminantsSimulating and visualizing the propagation of dispersive contaminants Open environments characterized by sky-scrapers and deep urban canyonsOpen environments characterized by sky-scrapers and deep urban canyons Multiple Relaxation Time Lattice Boltzmann Model for flow simulationMultiple Relaxation Time Lattice Boltzmann Model for flow simulation GPU accelerated computation and visualizationGPU accelerated computation and visualizationOverview Simulating and visualizing the propagation of dispersive contaminantsSimulating and visualizing the propagation of dispersive contaminants Open environments characterized by sky-scrapers and deep urban canyonsOpen environments characterized by sky-scrapers and deep urban canyons Multiple Relaxation Time Lattice Boltzmann Model for flow simulationMultiple Relaxation Time Lattice Boltzmann Model for flow simulation GPU accelerated computation and visualizationGPU accelerated computation and visualization GPU Acceleration Local operations in LBM are accelerated by GPULocal operations in LBM are accelerated by GPU Data layout:Data layout: One state variable stored in one volumeOne state variable stored in one volume Each volume packed into a series of 2D texturesEach volume packed into a series of 2D textures Boundary link information packed into small 2D texturesBoundary link information packed into small 2D textures Computation:Computation: LBM operations mapped to fragment programLBM operations mapped to fragment program Results stored in pixel buffers and copied back to textures for next stepResults stored in pixel buffers and copied back to textures for next step Simulation and visualization on same GPU, reducing data transferSimulation and visualization on same GPU, reducing data transfer GPU Acceleration Local operations in LBM are accelerated by GPULocal operations in LBM are accelerated by GPU Data layout:Data layout: One state variable stored in one volumeOne state variable stored in one volume Each volume packed into a series of 2D texturesEach volume packed into a series of 2D textures Boundary link information packed into small 2D texturesBoundary link information packed into small 2D textures Computation:Computation: LBM operations mapped to fragment programLBM operations mapped to fragment program Results stored in pixel buffers and copied back to textures for next stepResults stored in pixel buffers and copied back to textures for next step Simulation and visualization on same GPU, reducing data transferSimulation and visualization on same GPU, reducing data transfer Visualization Rendering of building:Rendering of building: Building textures from real imagesBuilding textures from real images Reserve texture memory for LBM simulationReserve texture memory for LBM simulation Shader program adds weathering and cracks to texturesShader program adds weathering and cracks to textures Rendering of smoke: Rendering of smoke: Splatting of smoke particles Splatting of smoke particles Splats distorted for correct projection Splats distorted for correct projection Half angle slicing for self-shadowing Half angle slicing for self-shadowingVisualization Rendering of building:Rendering of building: Building textures from real imagesBuilding textures from real images Reserve texture memory for LBM simulationReserve texture memory for LBM simulation Shader program adds weathering and cracks to texturesShader program adds weathering and cracks to textures Rendering of smoke: Rendering of smoke: Splatting of smoke particles Splatting of smoke particles Splats distorted for correct projection Splats distorted for correct projection Half angle slicing for self-shadowing Half angle slicing for self-shadowing Lattice Boltzmann Model (LBM) LBM models Boltzmann particle dynamics on a regular latticeLBM models Boltzmann particle dynamics on a regular lattice Streaming and collision in discrete time stepsStreaming and collision in discrete time steps 2 nd order space-time accurate CFD method2 nd order space-time accurate CFD method Advantages: GPU accelerated, complex boundary, easy to implement, multi-resolution, sensor feedbackAdvantages: GPU accelerated, complex boundary, easy to implement, multi-resolution, sensor feedback Lattice Boltzmann Model (LBM) LBM models Boltzmann particle dynamics on a regular latticeLBM models Boltzmann particle dynamics on a regular lattice Streaming and collision in discrete time stepsStreaming and collision in discrete time steps 2 nd order space-time accurate CFD method2 nd order space-time accurate CFD method Advantages: GPU accelerated, complex boundary, easy to implement, multi-resolution, sensor feedbackAdvantages: GPU accelerated, complex boundary, easy to implement, multi-resolution, sensor feedback Smoke in city model Original façade Façade variation Sensor Feedback Two methods:Two methods: Incorporate sensor data as body forceIncorporate sensor data as body force Modify boundary nodes affecting sensor readingsModify boundary nodes affecting sensor readings Sensor Feedback Two methods:Two methods: Incorporate sensor data as body forceIncorporate sensor data as body force Modify boundary nodes affecting sensor readingsModify boundary nodes affecting sensor readings Snapshots of simulation with smoke and flow streamlines Streamlines in Time Square Single GPU Results West Village area of New York City (10 blocks)West Village area of New York City (10 blocks) Lattice size: 90x30x60 with grid unit 3.8mLattice size: 90x30x60 with grid unit 3.8m Speedup (GPU/CPU): 7Speedup (GPU/CPU): 7 Single GPU Results West Village area of New York City (10 blocks)West Village area of New York City (10 blocks) Lattice size: 90x30x60 with grid unit 3.8mLattice size: 90x30x60 with grid unit 3.8m Speedup (GPU/CPU): 7Speedup (GPU/CPU): 7 Multi-GPU Results Time Square area of New York City (110 blocks)Time Square area of New York City (110 blocks) Lattice size: 320x80x320 with grid unit 4.5mLattice size: 320x80x320 with grid unit 4.5m Speedup on 30 nodes (GPU cluster/CPU cluster): 4-5Speedup on 30 nodes (GPU cluster/CPU cluster): 4-5 Multi-GPU Results Time Square area of New York City (110 blocks)Time Square area of New York City (110 blocks) Lattice size: 320x80x320 with grid unit 4.5mLattice size: 320x80x320 with grid unit 4.5m Speedup on 30 nodes (GPU cluster/CPU cluster): 4-5Speedup on 30 nodes (GPU cluster/CPU cluster): 4-5 Acknowledgement NSF CCR NSF CCR Department of Homeland Security, Environment Measurement LaboratoryDepartment of Homeland Security, Environment Measurement LaboratoryAcknowledgement NSF CCR NSF CCR Department of Homeland Security, Environment Measurement LaboratoryDepartment of Homeland Security, Environment Measurement Laboratory