River reach meshing question

CGM · February 29, 2012, 02:22

Hello everyone,

This is my first post on this top notch forum and I have a question regarding meshing a river reach. Please see the attached image for a plan view of the geometry file I am working with. (I apologize for the size)

My goal is to run a free surface shallow water model of this portion of the river and I'm wondering what the best meshing option would be? Multiple cartesian meshes, a single mesh, or a cylindrical mesh? Also, can the cartesian meshes be rotated to better represent a boundary condition?

Thank you in advance for any assistance!

melissa · February 29, 2012, 10:39

If you are going to use the shallow water model then you should use 1 mesh block-cartesian and only 2 cells in the z-direction. There is an example in the graphical user interface that you consult.

CGM · February 29, 2012, 16:51

Thank you for the response Melissa,

A single cartesian mesh block would be ideal, but the geometry of this river bend would benefit from a rotated boundary condition applied to the downstream end of the reach.

Can a cartesian mesh block be rotated, and also, can a shallow water model handle a multi block mesh if needed?

melissa · March 1, 2012, 12:27

Currently there is no way to have a rotated mesh.

Shallow water can have multiple mesh blocks you just have to be sure that in the z-direction there are 2 cells and 1 of those cells must contain the solid geometry and the fluid.

Cells are not allocated in the solid.

melissa · March 1, 2012, 12:51

sorry I cut off at the end

cells are not allocated in the solid unless heat transfer is activated which I assume you will not have it activated.

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February 29, 2012, 10:39		#2
melissa Member MC Join Date: Mar 2009 Posts: 56 Rep Power: 17	If you are going to use the shallow water model then you should use 1 mesh block-cartesian and only 2 cells in the z-direction. There is an example in the graphical user interface that you consult.

February 29, 2012, 16:51		#3
CGM New Member Chris G Join Date: Feb 2012 Posts: 2 Rep Power: 0	Thank you for the response Melissa, A single cartesian mesh block would be ideal, but the geometry of this river bend would benefit from a rotated boundary condition applied to the downstream end of the reach. Can a cartesian mesh block be rotated, and also, can a shallow water model handle a multi block mesh if needed?

March 1, 2012, 12:27		#4
melissa Member MC Join Date: Mar 2009 Posts: 56 Rep Power: 17	Currently there is no way to have a rotated mesh. Shallow water can have multiple mesh blocks you just have to be sure that in the z-direction there are 2 cells and 1 of those cells must contain the solid geometry and the fluid. Cells are not allocated in the solid.

March 1, 2012, 12:51		#5
melissa Member MC Join Date: Mar 2009 Posts: 56 Rep Power: 17	sorry I cut off at the end cells are not allocated in the solid unless heat transfer is activated which I assume you will not have it activated.