Computational fluid dynamics using Graphics Processing Units: Challenges and opportunities

A new paradigm for computing fluid flows is the use of Graphics Processing Units (GPU), which have recently become very powerful and convenient to use. In the past three years, we have implemented five different fluid flow algorithms on GPUs and have obtained significant speed-ups over a single CPU. Typically, it is possible to achieve a factor of 50-100 over a single CPU. In this review paper, we describe our experiences on the various algorithms developed and the speeds achieved

Development of Parallel CFD Solver for Three Dimnesional Unstructured Grid

The current work develops a general purpose Navier-Stokes semi implicit solver capable of handling three-dimensional unstructured grids. The ow needs to be laminar and incompressible. Species transport equation can also be solved using a segregated algorithm. Pressure Poisson equation that takes most of the solving time has been parallelized using CUDA programming language on GPU, with Algebraic Multigrid for orthogonal unstructured grids. Domain decomposition has been done using greedy colouring method. Single phase jets have been studied in presence of walls has been studied, which is of interest in Internal Combustion engines. Large Eddy simulation (LES) modeling has been employed for simulating turbulent ows using Static Smagrosnky model. Validations have been presented for turbulent round and plane jets. Laminar and turbulent coaxial jets for different velocity ratios for has been simulated and the effect of faster annular jet on the core of inner jet is analyzed and presented

numerical study of steady flow inside a lid-driven square cavity for Reynolds number up to 50000

The flow inside a lid-driven square cavity have been imposed a wide controversy during these last decades.Multiple studies found to exist in the literature included this case, which is widely used for benchmarking in computational fluid dynamic due to the simplicity of geometry. some classes of studies have investigated the existence of steady flow in the driven cavity, they found a steady 2D numérical solution until 35000 value of Reynolds number.However, other classes of studies have stated that the flow in driven cavity submitted to a hydrodynamic instability and they illustrated a continuation méthode to locate the point at which a Hopf bifurcation occurs leading to a transition from a steady flow to unsteady.In the shade of these studies and with this uncertainty surrounding this subject we wanted to get more clarification especially for steady flow solutions.The present study represents a numerical computation for steady flow inside a lid-driven square cavity, the governing equation is solved using a finite volume method based on second order scheme of accuracy. Steady solutions are obtained for Reynolds numbers ascending from 100 to 50000, using a resolution of 1024 x1024 grid point. A good agreement with previous results in the literature, the work was done in this paper including proprieties of flow in the center of primary and secondary vortices, velocity components and numérical values for stream function and vorticity which assure a good example for benchmarking purposes

Structured-grid multigrid with Taylor-Hood finite elements

Recent years have seen renewed interest in the numerical solution of the Stokes Equations. At the same time, new computational architectures, such as GPUs and manycore processors, naturally perform best with the regular data access and computation patterns associated with structured-grid discretisations and algorithms. While many preconditioning approaches ignore the underlying mesh geometry, our approach is to develop a structured-grid implementation, taking advantage of the highly structured data-access patterns and employing stencil-based calculations. This opens up many opportunities for fine-grained parallelism, allowing us to take advantage of multicore and accelerated architectures. In this thesis, we will consider an implementation of a structured-grid monolithic Multigrid approach for Q2-Q1 finite-element discretisations, comparing its efficiency to an unstructured grid solver implemented in Trilinos. With the aim to eventually target large heterogeneous systems, we will discuss an implementation for moving from a serial code to the GPU by means of OpenCL and compare the efficiency of all three versions. Speedup factors of about 6.3x were observed for the GPU implementation over a serial implementation in Trilinos for a problem on a 768x768 mesh in 2D