Construction of CAD-based unstructured mesh models for 3D Navier-Stokes simulations

2007 ◽  
pp. 608-616
Author(s):  
W. N. Dawes
Keyword(s):  
Unstructured Mesh ◽  
Navier Stokes ◽  
Mesh Models

Profiled End-Wall Design Using an Adjoint Navier-Stokes Solver

2006 ◽  
Author(s):  
Roque Corral ◽  
Fernando Gisbert
Keyword(s):  
Kinetic Energy ◽  
Cost Function ◽  
Unstructured Mesh ◽  
Low Pressure ◽  
Navier Stokes ◽  
Low Pressure Turbine ◽  
Gradient Based ◽  
Parallel Multigrid ◽  
End Wall ◽  
Discrete Formulation

A methodology to minimize blade secondary losses by modifying turbine end-walls is presented. The optimization is addressed using a gradient-based method, where the computation of the gradient is performed using an adjoint code and the secondary kinetic energy is used as a cost function. The adjoint code is implemented on the basis of the discrete formulation of a parallel multigrid unstructured mesh Navier-Stokes solver. The results of the optimization of two end-walls of a low pressure turbine row are shown.

scholarly journals The Finite-volumE Sea ice–Ocean Model (FESOM2)

2016 ◽  
Author(s):  
Sergey Danilov ◽  
Dmitry Sidorenko ◽  
Qiang Wang ◽  
Thomas Jung
Keyword(s):  
Sea Ice ◽  
Ocean Circulation ◽  
Unstructured Mesh ◽  
Circulation Model ◽  
Ocean Model ◽  
Arbitrary Lagrangian Eulerian ◽  
Major Step ◽  
Vertical Coordinate ◽  
Intercomparison Project ◽  
Mesh Models

Abstract. Version 2 of the unstructured-mesh sea ice – ocean circulation model FESOM is presented. It builds upon FESOM1.4 (Wang et al., 2014, Geosci. Mod. Dev., 7, 663–693) but differs by its dynamical core (finite volumes instead of finite elements) and is formulated using the Arbitrary Lagrangian Eulerian (ALE) vertical coordinate, which increases model flexibility. The model inherits the framework and sea ice model from the previous version, which minimizes the efforts needed from a user to switch from one version to the other. The ocean states simulated with FESOM1.4 and FESOM2.0 driven by CORE-II forcing are compared on a mesh used for CORE-II intercomparison project. Additionally the performance on an eddy-permitting mesh with uniform resolution is discussed. The new version improves numerical efficiency of FESOM in terms of CPU time by at least three times while retaining its fidelity in simulating sea ice and ocean. From this it is argued that FESOM2.0 provides a major step forward in establishing unstructured-mesh models as valuable tools in climate research.

scholarly journals Simulating Unsteady Turbomachinery Flows on Unstructured Meshes Which Adapt Both in Time and Space

1993 ◽  
Author(s):  
W. N. Dawes
Keyword(s):  
Unsteady Flow ◽  
Strouhal Number ◽  
Time Scales ◽  
Vortex Shedding ◽  
Unstructured Mesh ◽  
Good Control ◽  
Adaptive Methods ◽  
Navier Stokes ◽  
Time And Space ◽  
Standard Problem

The objective of this paper is to stimulate study of application of solution-adaptive methods to unsteady turbomachinery flows. First, the extension of an existing 3D unstructured mesh Navier-Stokes solver to cover unsteady flows is described. Then the basic method is validated for the classic case of vortex shedding from a cylinder. Next, the modification of the data structures of the algorithm into a strict parent-child hierarchy are described; this enables refinement and derefinement to take place sufficiently economically for mesh adaption to take place over time scales significantly smaller than the characteristic time scales of the unsteady flow. Application to the vortex shedding from a cylinder showed that the unsteady solution obtained on an adaptively (locally) refined mesh was essentially the same as that from a reference, uniformly (globally) refined mesh, both simulations predicting a Strouhal number of 0.20. By contrast, a basic unrefined mesh predicted a small but systematically lower shedding frequency and Strouhal number of 0.17. Finally, both Euler and Navier-Stokes solutions are obtained for the standard problem of the interaction of stator wakes with the following rotor row. The adaptively refined solution displays very good control over the wake resolution and minimises false smoothing of the wake structures as they propagate. Good qualitative agreement is observed in comparison with other published numerical simulations. It is concluded that the application of unstructured mesh methods which adapt both in time and space to unsteady flow problems is both viable and promising.

Exploring Unstructured Mesh Adaptation for Hybrid Reynolds-Averaged Navier–Stokes/Large Eddy Simulation

2020 ◽  
Author(s):  
Michael A. Park ◽  
William L. Kleb ◽  
William K. Anderson ◽  
Stephen L. Wood ◽  
Aravind Balan ◽  
...  
Keyword(s):  
Large Eddy Simulation ◽  
Unstructured Mesh ◽  
Mesh Adaptation ◽  
Navier Stokes ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Reynolds Averaged Navier Stokes

scholarly journals Parallel Performance Investigations of an Unstructured Mesh Navier-Stokes Solver

2002 ◽  
Vol 16 (4) ◽  
pp. 395-407 ◽  
Author(s):  
Dimitri J. Mavriplis
Keyword(s):  
Shared Memory ◽  
Unstructured Mesh ◽  
Communication Strategy ◽  
Navier Stokes ◽  
Parallel Performance ◽  
Communication Models ◽  
Cache Efficient ◽  
And Performance ◽  
Memory Architectures ◽  
Single Processor

Summary The implementation and performance of a hybrid OpenMP/ MPI parallel communication strategy for an unstructured mesh computational fluid dynamics code is described. The solver is cache efficient and fully vectorizable, and is parallelized using a two-level hybrid MPI-OpenMP implementation suitable for shared and/or distributed memory architectures, as well as clusters of shared memory machines. Parallelism is obtained through domain decomposition for both communication models. Single processor computational rates as well as scalability curves are given on various architectures. For the architectures studied in this work, the OpenMP or hybrid OpenMP/MPI communication strategies achieved no appreciable performance benefit over an exclusive MPI communication strategy.

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