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the step size used in Gridgen

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Old   October 1, 2002, 15:49
Default the step size used in Gridgen
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yang
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Hi there, I've got a confusing problem with the spacing size when using Gridgen.

As we all know, based on the grid generated by Gridgen, we could discretise N-S equations on a rectangular domain(computational domain). The question is how to determine the step size since Gridgen doesn't provide any information on this.

I've read many articles, it seems like the choice of stepsize in the computational domain is arbitrary. For convenience, many people choose 1.0 as the stepsize. Is it true?

Thanks a lot.
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Old   October 1, 2002, 23:19
Default Re: the step size used in Gridgen
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versi
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The grid size in computational domain will not affect the solution, rather, it is the metric coefficient that will determine the solution.
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Old   October 2, 2002, 10:32
Default Re: the step size used in Gridgen
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yang
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Thanks versi. Since the grid size plays no role in computation, what about the Courant number,which involves step size,i.e. dx?
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Old   October 3, 2002, 04:50
Default Re: the step size used in Gridgen
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papiya roy
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hi i really want to know about the grid generation please let me inform. thankig you papiya roy
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Old   October 4, 2002, 05:09
Default Re: the step size used in Gridgen
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versi
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In curvilinear coordinates

dt = CFL/ ( |U_contra| + |V_contra| + a sqrt ( (\xi_x)^2+ (\xi_y)^2 +(\eta_x)^2+(\eta_y)^2) ), so again you see that only metric coefficents are concerned. Dx is already taken into account in metric coefficient.

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