fvSchemes & fvSolutions

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snappyHexMesh tutorial for a simple Geometry

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In this section I will address how to use the snappyHexMesh tool to mesh a Cylinder. We can either create an stl file for the cylinder - place it inside the  triSurface/constant  folder and call the same into the background mesh, or a simple cylinder can be directly created by using the 'searchable cylinder' parameter within the snappyHexMeshDict.  cylinder     { type searchableCylinder;   point1 (0 0.0 -0.5);  point2    (0 0.0 0.5); radius 0.01585;     } A refined mesh can be viewed below. The radius of the cylinder is of the order e-02 which gives us some insight into what the cell size for the back ground mesh can be. The blockMesh for the background mesh will be addressed later. Next in line in the snappyHexMeshDict is the Refinement box parameter. This box defines how refinement around the cylinder and importantly how the wake refinement can be achieved. The refinement box separates the finer refinement from the background mesh grid.  refin
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snappyHexMesh Tutorial For a Complex Geometry and External Aerodynamics

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The geometry chosen for external fluid dynamics simulation is that of an offshore structure. In that, a deep-draft semi-submersible structure  is scaled scaled down to a value  of 0.01 (scaled down by a factor of 100). The semi-submersible structures are employed at locations where the oil extraction from the sea bed is considerably deep. These are movable structures which are half submerged during application. A working deck comes right on top of the structure where the cranes and oil rigs are fitted. The semi-submersible consists of four hull appendages which connect the working deck with a pontoon structure. The pontoon structure gives buoyancy to the semi-submersible in deep waters but does not come directly in contact with the ocean bed.  Figure No.1: DDS The effects of flow induced vibration on the above four columns during high flow currents is indeed the case of interest. Once a good mesh is achieved, the platform is set for the study on the effects of Vortex Induced
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How to refine a 2D cylinder blockMesh

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For the audience who do not know what a 'blockMesh' is, it is a Mesh tool which comes along with the open-source software called 'openFoam'. Many university students and researchers have begun using openFoam for their flow simulation problems. There is another mesh tool called the 'snappyHexMesh', which is normally employed to mesh complex geometry for the flow simulations. In this post, although, I will restrict the information only to a 2D cylinder mesh - that is, a 2D mesh housing a cylinder. I will largely talk about how to play around with parameters in the blockMeshDict in order to obtain a refined mesh. I will also briefly talk about the turbulence models that can be used to run a high Reynolds number simulation on a refined grid. If you are wondering where to start or where to access a case file, you can check the following website: http://www.wolfdynamics.com/. They have an extended compilation of case files and tutorials working up to almost 1.
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