Advection Schemes

Advection is the numerical mechanism of transporting a quantity (velocity, temperature, etc.) through the solution domain. Five advection methods are available in Autodesk® CFD.

To change the advection scheme:

  1. Open the Solve dialog. (Right click off the model, and select Solve.)
  2. On the Control tab, click Solution Control.
  3. On the Solution Controls dialog, click Advection.
  4. Select the desired advection scheme from the list.

The recommended applications of the four advection schemes are described in the table below:

ADV 1

(Monotone streamline upwind)

This was the previous default scheme for nearly all analyses (except rotating regions). It is the “work horse,” and is recommended as a starting point for analysis that have issues with ADV 5.

  • Numerically stable
  • Recommended for meshes aligned with flow direction
  • Numerically diffusive for meshes not aligned with flow
  • Works well for geometries with numerous internal obstructions
  • Works well for extruded meshes
  • Works well for distributed resistances assigned to surface parts.
   

ADV 2

(Petrov-Galerkin)

  • Moderate numerical stability (less than ADV 1)
  • Less numerical diffusion for random meshes. Models with random meshes have large domains, and often feature unrestricted external flow. Examples include:
    • AEC and Displacement Ventilation
    • Large External Flow Domains
    • Data Centers
  • Recommended for pressure driven flows
  • Recommended for compressible flows
  • Default for scalar and energy transport equations
  • Default for rotating region analyses
   

ADV 3

(Flux based scheme)

  • Numerically unstable for most flows
  • Can only be used for INCOMPRESSIBLE flows
  • Cannot be used for moving solids analyses
  • Specially tuned for drag or external flow problems
  • Mesh Enhancement must be invoked.
   

ADV 4

(Min-Mod scheme--Petrov-Galerkin variant)

  • Moderate numerical stability (less than ADV 1)
  • Specially tuned for flows in long narrow ducts
   

ADV 5

(Modified Petrov-Galerkin)



ADV 5 is the new default advection scheme, old studies retain their settings but new studies default to ADV 5.ADV 5 is a more stable variation of ADV 2, the Petrov-Galerkin advection scheme. It is suitable for all application types recommended with ADV 2, but typically produces more globally conservative results. ADV 5 has demonstrated improvements over ADV 2 in the following areas:

  • Accuracy of recirculating and secondary flows
  • Pressure drop prediction
  • Natural convection stability
  • Compressible flow accuracy and stability
  • Rotating (turbomachinery) and Motion accuracy and stability
  • Energy balance stability
  • Distributed resistances assigned to volumes.

For an example of changing the Advection Scheme

Parent topic: Solution Control