733 research outputs found
Parallel Anisotropic Unstructured Grid Adaptation
Computational Fluid Dynamics (CFD) has become critical to the design and analysis of aerospace vehicles. Parallel grid adaptation that resolves multiple scales with anisotropy is identified as one of the challenges in the CFD Vision 2030 Study to increase the capacity and capability of CFD simulation. The Study also cautions that computer architectures are undergoing a radical change and dramatic increases in algorithm concurrency will be required to exploit full performance. This paper reviews four different methods to parallel anisotropic grid generation. They cover both ends of the spectrum: (i) using existing state-of-the-art software optimized for a single core and modifying it for parallel platforms and (ii) designing and implementing scalable software with incomplete, but rapidly maturating functionality. A brief overview for each grid adaptation system is presented in the context of a telescopic approach for multilevel concurrency. These methods employ different approaches to enable parallel execution, which provides a unique opportunity to illustrate the relative behavior of each approach. Qualitative and quantitative metric evaluations are used to draw lessons for future developments in this critical area for parallel CFD simulation
Finite Element Flow Simulations of the EUROLIFT DLR-F11 High Lift Configuration
This paper presents flow simulation results of the EUROLIFT DLR-F11
multi-element wing configuration, obtained with a highly scalable finite
element solver, PHASTA. This work was accomplished as a part of the 2nd high
lift prediction workshop. In-house meshes were constructed with increasing mesh
density for analysis. A solution adaptive approach was used as an alternative
and its effectiveness was studied by comparing its results with the ones
obtained with other meshes. Comparisons between the numerical solution obtained
with unsteady RANS turbulence model and available experimental results are
provided for verification and discussion. Based on the observations, future
direction for adaptive research and simulations with higher fidelity turbulence
models is outlined.Comment: 52nd Aerospace Sciences Meetin
Investigation of parallel efficiency of an adaptive flow solver
AbstractParallel efficiency, in a domain decomposition based approach, strongly depends on a partitioning quality. For an adaptive simulation partitioning quality is lost due to the dynamic modification of the computational mesh. Maintaining high efficiency of parallelization requires rebalancing of the numerical load. This paper presents numerical experiment with adaptive and dynamically load balanced flow application. It is shown that through a relatively inexpensive process of repartitioning high parallel efficiency is maintained
Scalable Recovery-based Adaptation on Quadtree Meshes for Advection-Diffusion-Reaction Problems
We propose a mesh adaptation procedure for Cartesian quadtree meshes, to
discretize scalar advection-diffusion-reaction problems. The adaptation process
is driven by a recovery-based a posteriori estimator for the -norm
of the discretization error, based on suitable higher order approximations of
both the solution and the associated gradient. In particular, a metric-based
approach exploits the information furnished by the estimator to iteratively
predict the new adapted mesh. The new mesh adaptation algorithm is successfully
assessed on different configurations, and turns out to perform well also when
dealing with discontinuities in the data as well as in the presence of internal
layers not aligned with the Cartesian directions. A cross-comparison with a
standard estimate--mark--refine approach and with other adaptive strategies
available in the literature shows the remarkable accuracy and parallel
scalability of the proposed approach
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