CFD Online Logo CFD Online URL
Home > Forums > General Forums > Main CFD Forum

How to satisfy GCL in FD method

Register Blogs Members List Search Today's Posts Mark Forums Read

LinkBack Thread Tools Search this Thread Display Modes
Old   March 10, 2003, 03:15
Default How to satisfy GCL in FD method
Xiong Yan
Posts: n/a
I want to compute unsteady flow around flying bird and insect. The bird or insect's wing is flexible. So the computed meshs are flexible deformation. The bird or insect's flow Re Number is very slow(<1000). The solved N-S equations is incompressible, now i can compute incompressible flow with Rogers's method(Steady and Unsteady Solutions of the Incompressible Navier-Stokes Equations Vol.29, No.4, April 1991 AIAA Journal). If i want to compute flexible wing's flow, the Rogers's solver must be satisfy GCL. But i don't how to let Rogers's incompressible solver satify GCL. Would u give me some advice about GCL, 3x

--Thanks for your time!
  Reply With Quote

Old   March 10, 2003, 14:28
Default Re: How to satisfy GCL in FD method
Posts: n/a
The classic reference is a paper by Thomas and Lombard (don't have the citation with me, should be an AIAA Journal article or paper), but the essence of the approach is the following, assuming you have cast your equations in body-fitted coordinates so the transformation metrics are carried in the system of equations-

Apply the coninuity equation to a uniform freestream.

Expand out derivatives, i.e.

d(q/J)/dx = 1/J*dq/dx - q/J**2*dJ/dx

Recognize that all terms like dq/dx -> 0, and what is left is a differential equation for the evolution of the Jacobian in time that must be satisfied at each timestep as part of your overall system.

A more general approach is laid out by Marcel Vinokur, but again I don't have the citation handy. Try doing a google on Vinokur - the paper deals with a comparison of finite difference and finite volume methods.
  Reply With Quote


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
[Gmsh] discretizer - gmshToFoam Andyjoe OpenFOAM Meshing & Mesh Conversion 13 March 14, 2012 04:35
Fluent 6.3.26 vs 12.1 and partition method Anorky FLUENT 0 April 27, 2010 10:55
Comparison: Finite Volume Method vs. Analytic Method m-fry Main CFD Forum 1 April 20, 2010 14:40
Code for most powerfull FDV Method D.S.Nasan Main CFD Forum 6 September 4, 2008 02:08
Help about the preconditioner in gmres method Dan Gao Main CFD Forum 3 July 5, 2008 01:18

All times are GMT -4. The time now is 18:56.