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

Numerical oscillations Roe solver shallow water equations

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

LinkBack Thread Tools Display Modes
Old   February 21, 2012, 06:31
Default Numerical oscillations Roe solver shallow water equations
New Member
Join Date: Jul 2010
Posts: 14
Rep Power: 7
RicardoGoncalves is on a distinguished road
Dear all,
I am using a finite volume shallow water model which uses the Roe Riemann solver. The scheme is only of 1st order and is applied to a structured rectangular grid, but I am still getting some nasty oscillations when simulating flows over a rather complex topography.
As far as I understand, this first order scheme should be stable (although highly diffusive); so my first guess for the cause of the oscillations is the treatment of the source terms (in this case bed topography).
Does anyone have a better guess/solution for this problem?
RicardoGoncalves is offline   Reply With Quote

Old   March 5, 2012, 04:03
New Member
Join Date: Mar 2012
Posts: 8
Rep Power: 5
Fabian82 is on a distinguished road
Dear RicardoGoncalves

Your problem is most likely be related to the source term. When the discretization errors of the Roe solver and the source term are not compatible, errors and noise may grow in time without any physical forcing. Your solver will therefore not be able to maintain a 'quiet' water state over a complex topography. A possible solution to this problem are so-called 'well-balanced schemes' which can be found in numerous formulations in literature, e.g. by modifying the interface reconstruction or by upwinding the source term at the interfaces.

Best wishes
Fabian82 is offline   Reply With Quote


finite volume, oscillation, riemann, roe, shallow water

Thread Tools
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 On
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
Numerical oscillations in LES due to mesh refinement Soder OpenFOAM 0 June 14, 2011 10:10
Vorticity in inviscid shallow water equations sonsiest Main CFD Forum 0 June 7, 2011 14:10
roe solver with entropy fix mehdi Main CFD Forum 1 February 26, 2006 06:36
Navier-stokes equations and iterative solver?? wuliang Main CFD Forum 2 January 13, 2003 23:28
multi-layer shallow water or Sigma coordinate? Hadian Main CFD Forum 0 August 8, 2002 09:53

All times are GMT -4. The time now is 20:41.