Laminar Flow Past a Backward Facing Step

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Incompressible subsonic flow past a two-dimensional backward-facing step is modeled to estimate the laminar reattachment length (i.e., the point where the separation bubble disappears on the channel floor behind the step). This is a step-by-step guided introductory tutorial for setting up a flow model in CFD-ACE+.


This tutorial introduces the user to the flow module in CFD-ACE+ and discusses the following model setup topics in detail:

  • Importing a grid file into CFD-ACE.
  • Setting model properties.
  • Setting problem type.
  • Setting volume/boundary/initial conditions.
  • Setting solver control properties.
  • Requesting printed and graphical output.
  • Submitting model to obtain a solution.
  • Checking for solution convergence.


If you have never used CFD-ACE+ or any other CFD tools, this is a good place to start. The backward-facing step is a canonical problem widely used as a validation test case to compare CFD code predictions with experiments in subsonic and especially in the supersonic flow regimes.

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