CFL condition. - FAQS.TIPS

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Does gmsh always output the nodes and elements of a mesh in ascending order?

I just started using gmsh for 2D triangulations and I'm observing that both the nodes and elements are being outputted in ascending order (consecutively). This is good as it makes reading the data...

07 August 2017 8,420 8 View

Are there any convergence results for well-balanced methods?

09 October 2016 2,399 0 View

Does anyone have the English version of the de Saint Venant paper in which he derived the channel model?

I need the English version of this paper which was publish in 1871.

07 August 2015 281 3 View

Does anyone know of any freely available tool (pre- and post-processor) that can be linked to a C++ solver?

I need a well developed pre- and post-processor that can generate complex meshes and provide all the functionalities needed to solve flow problems in it. And also allow visualizations. The goal is...

01 February 2015 3,680 16 View

What numerical flux solver for hyperbolic conservation laws, is your favorite?

10 November 2014 9,892 1 View

Does anyone have experience in modeling strategy of relaxation?

Given a PDE model with some constraints restricting the range of values of model quantities, how does one apply the idea of relaxation to such a model? Any idea or references on relaxation idea of...

08 September 2014 1,406 12 View

What condition(s) hold on fluid particles across a line or surface inside a fluid domain?

Consider a 1-D flow along x-axis with z-axis in vertical direction. The fluid domain is bounded below by a fixed bottom at z=b(x) and above by free-surface at z = h(x,t)+b(x), with h= height of...

07 August 2014 3,980 6 View

Does anyone have a code for a 1-D grid that is adaptable and can be shared with me?

I have an urgent need for 1-D adaptive grid for my 1-D hyperbolic code. I will be very happy if anyone can assist me with this.

07 August 2014 5,459 9 View

Does anyone have experience with approximate Riemann Solvers?

07 August 2014 606 6 View

What refinement indicators currently exist for hyperbolic system of PDEs, in particular, the shallow water equations?

What refinement indicators currently exist for hyperbolic system of PDEs, in particular, the shallow water equations? which is your favourite and why? also provide references.

06 July 2014 9,827 3 View

error in running a model in Abaqus

Excessive rotation of nodes in node set ErrNodeExcessRotation-Step1

17 August 2021 0 0 View

error in modelling model in Abaqus

Excessive rotation of nodes in node set ErrNodeExcessRotation-Step1

17 August 2021 0 0 View

MD MOE RMSD

How to calculate the RMSD values for a MD simulation using MOE?

07 August 2021 0 0 View

MD MOE RMSD

How to calculate the RMSD values for a MD simulation using MOE?

07 August 2021 0 0 View

MGL tools

20 June 2021 0 0 View

fatal error

When I tried to energy minimization my system, I got fatal error as below. Fatal error: Atomtype opls_116 not found Although I've already added this line: ; include water #include "oplsaa.ff/spc.itp" to [molecultype] directive in my topology.

16 June 2021 0 0 View

fatal error

16 June 2021 0 0 View

fatal error

16 June 2021 0 0 View

fatal error

16 June 2021 0 0 View

i have some problem with chtMultiRegionSimpleFoam

--> FOAM FATAL ERROR: Maximum number of iterations exceeded From function Foam::scalar Foam::species::thermo::T(Foam::scalar, Foam::scalar, Foam::scalar, Foam::scalar (Foam::species::thermo::*)(Foam::scalar, Foam::scalar) const, Foam::scalar (Foam::species::thermo::*)(Foam::scalar, Foam::scalar) const, Foam::scalar (Foam::species::thermo::*)(Foam::scalar) const) const [with Thermo = Foam::hConstThermo >; Type = Foam::sensibleEnthalpy; Foam::scalar = double; Foam::species::thermo = Foam::species::thermo >, Foam::sensibleEnthalpy>] in file /home/ubuntu/OpenFOAM/OpenFOAM-4.1/src/thermophysicalModels/specie/lnInclude/thermoI.H at line 66. FOAM aborting #0 Foam::error::printStack(Foam::Ostream&) at ??:? #1 Foam::error::abort() at ??:? #2 Foam::heRhoThermo >, Foam::sensibleEnthalpy> > > >::calculate() at ??:? #3 Foam::heRhoThermo >, Foam::sensibleEnthalpy> > > >::correct() at ??:? #4 ? at ??:? #5 __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6" #6 ? at ??:?

24 March 2021 0 0 View

Chinedu Nwaigwe

I think am already getting some results for inviscid burgers. I still need some insights.

I used Cflcof=dt(Smax)/dx, where 0

Marco Ceze

Hi Chinedu,

The optimal CFL should be close to 1 as, in linear problems, Godunov's method is the exact shift operator at CFL =1.

Now, in the case of Burgers' equation, the scheme will have 1st order level of dissipation so the numerical solution may only resemble the exact solution. Did you try refining your mesh to see if the numerical solution apprximates the exact solution?

Good luck,

Marco