GAMES Webinar 2022 – 239期(复杂流形结构下的湍流仿真及双向流固耦合) | Chaoyang Lyu(ShanghaiTech University)，Qiaodong Cui(Inkbit)
【GAMES Webinar 2022-239期】(模拟专题-复杂流形结构下的湍流仿真及双向流固耦合)
报告嘉宾：Chaoyang Lyu(ShanghaiTech University)
报告题目：Fast and Versatile Fluid-Solid Coupling for Turbulent Flow Simulation
The intricate motions and complex vortical structures generated by the interaction between fluids and solids are visually fascinating. However, reproducing such a two-way coupling between thin objects and turbulent fluids numerically is notoriously challenging and computationally costly: existing approaches such as cut-cell or immersed-boundary methods have difficulty achieving physical accuracy, or even visual plausibility, of simulations involving fast-evolving flows with immersed objects of arbitrary shapes. In this paper, we propose an efficient and versatile approach for simulating two-way fluid-solid coupling within the kinetic (lattice-Boltzmann) fluid simulation framework, valid for both laminar and highly turbulent flows, and for both thick and thin objects. We introduce a novel hybrid approach to fluid-solid coupling which systematically involves a mesoscopic double-sided bounce-back scheme followed by a cut-cell velocity correction for a more robust and plausible treatment of turbulent flows near moving (thin) solids, preventing flow penetration and reducing boundary artifacts significantly. Coupled with an efficient approximation to simplify geometric computations, the whole boundary treatment method preserves the inherent massively parallel computational nature of the kinetic method. Moreover, we propose simple GPU optimizations of the core LBM algorithm which achieve an even higher computational efficiency than the state-of-the-art kinetic fluid solvers in graphics. We demonstrate the accuracy and efficacy of our two-way coupling through various challenging simulations involving a variety of rigid body solids and fluids at both high and low Reynolds numbers. Finally, comparisons to existing methods on benchmark data and real experiments further highlight the superiority of our method.
Chaoyang Lyu is a Ph.D. candidate in the School of Information Science and Technology, ShanghaiTech University. Prior to that, he received B.S. in software engineering from Harbin Institute of Technology, Weihai. Lyu is currently interested in the lattice Boltzmann simulation of fluid flows and computer graphics techniques, with a particular focus on fluid-solid coupling with arbitrary solid geometries, as well as thermal and compressible flow simulations with turbulence.
报告题目：Stable, Scalable Spectral Methods for Fluid Simulation
In this talk, we introduce Stable, Scalable Spectral Methods for Fluid Simulation. First, we introduce Scalable Laplacian Eigenfluids. In this method, we present a set of analytical basis functions that can be used to effectively represent the velocity field of the fluid. We show that by carefully applying the discrete sine and cosine transforms, the storage costs of the basis functions can be made completely negligible. The resulting algorithm is both faster and more memory-efficient than previous approaches. Next, we introduce a fast, expressive spectral method for simulating fluids over radial domains, including discs, spheres, cylinders, ellipses, spheroids, and tori. We do this by generalizing the approach of Laplacian Eigenfunctions, resulting in what we call spiral-spectral fluid simulations. We show basis functions that support scalable FFT-based reconstruction can be analytically constructed.
Qiaodong Cui studied computer graphics and received his Ph.D. at UCSB under the supervision of Professor Ted Kim. His research interests are in the area of physically based animation in computer graphics. He developed some efficient spectral based fluid simulation methods. Currently he’s a research engineer at Inkbit, a MIT startup focused on inkjet industrial 3D printing.
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