CFD Online Logo CFD Online URL
Home > Forums > Software User Forums > OpenFOAM > OpenFOAM Running, Solving & CFD

Numerical Theory and Implementation OpenFoam

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

LinkBack Thread Tools Search this Thread Display Modes
Old   October 24, 2021, 06:33
Default Numerical Theory and Implementation OpenFoam
Join Date: Jun 2021
Location: Germany
Posts: 92
Rep Power: 3
qutadah.r is on a distinguished road
Hello, I have a question regarding how openfoam solves equations for simulation. If someone can guide me through my thought process and tell me if its right... Please point me out if I have mistakes in my understanding.

1- we have a computational mesh or domain which we know with its vertices or nodes.

2- Discretize the NS equations using the FVM approach and make a local equation for each cell in the mesh using one of the discretization methods for each term in the equation. All will be cell-centered based.

3- Interpolation methods is used for the diffusion term and only that term to find the face values because we need them in the equation.

4- we need to make a global matrix and solve it iteratively using one of the iterative solvers, where we under-relax specific terms if they increase instability in solving our matrix. Where does preconditioning come into all of this?

*constructing a global matrix of 3 million cells in a steady state incompressible flow means we have 4 unknowns at each cell, which means 12 million unknowns in the equation?

5- We use one of the Algorithms to solve the pressure/velocity coupled momentum and continuity equations, and find the respective fields for each.

6- We solve using Initial and boundary conditions in our 0/ folder, however these values are also cell-centered.

7- nonorthogonal correctors are used to determine how many times the pressure equation is solved in a pressure/velocity coupling algorithm like the simple/piso.

8- we keep solving until we get a converged solution based on our residuals.

qutadah.r is offline   Reply With Quote


algorithm, numerical analysis, openfoam-6, theory

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
Wrong implementation of the Boussinesq assumption in heat transfer solvers diego_angeli OpenFOAM Running, Solving & CFD 15 February 7, 2022 19:14
OpenFoam background theory of implementation ssitank OpenFOAM 5 July 2, 2020 03:46
Reference Material for Immersed Boundary Solvers in OpenFoam utkunun OpenFOAM Programming & Development 9 September 22, 2017 09:30
Implementation of Inflow Data Generation Theory irishdave OpenFOAM Pre-Processing 4 March 3, 2014 09:29
Implementation of wall function with SA model Bala Main CFD Forum 0 October 7, 2004 23:54

All times are GMT -4. The time now is 00:43.