From 65bccf39525578eb0c763c3dd8ec4e4c9f9a7306 Mon Sep 17 00:00:00 2001 From: Christian Kolset Date: Tue, 23 Sep 2025 15:43:39 -0600 Subject: Added FTCS method to PDE.md --- tutorials/module_3/6_pde.md | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) (limited to 'tutorials') diff --git a/tutorials/module_3/6_pde.md b/tutorials/module_3/6_pde.md index 1f11b13..95d63c4 100644 --- a/tutorials/module_3/6_pde.md +++ b/tutorials/module_3/6_pde.md @@ -64,6 +64,9 @@ $$ Explicit methods +Forward-time central-space + based on forward euler method and central difference in space. + Simple Implicit methods Crank-Nicolson ADI @@ -71,7 +74,30 @@ ADI ### Hyperbolic Equations MacCormack Method +In computational fluid dynamics (CFD), the governing equations are the Navier-Stokes equations. For inviscid (no viscosity) compressible flow, these reduce to the Euler equations: +$$ +\frac{\partial u}{\partial t}+\frac{\partial f(u)}{\partial x} = 0 +$$ +where, $U$ is conserved variables. This equation is a hyperbolic PDE. + +Discretize domain: space and time + + + +Write fluxes: + + +MacCormack Algorithm +- Predictor +$$ +u^p_i = u^n_i - \frac{\Delta t}{\Delta x}(f^n_{i+1}-f^n_i) +$$ +- Corrector +$$ +u^{p+1}_i = \frac{1}{2}(u^n_i+u^p_i) - \frac{\Delta t}{2\Delta x}(f^p_{i}-f^n_{i-1}) +$$ +Method of characteristics ## Finite-Element Method General Approach -- cgit v1.2.3