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:
- Open the Solve dialog. (Right click off the model, and select Solve.)
- On the Control tab, click Solution Control.
- On the Solution Controls dialog, click Advection.
- 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.
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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
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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.
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ADV 4 (Min-Mod scheme--Petrov-Galerkin variant) | - Moderate numerical stability (less than ADV 1)
- Specially tuned for flows in long narrow ducts
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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.
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For an example of changing the Advection Scheme