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TITLE : 2D CONVECTION OF A SCALAR STEP IN A RECIRCULATING FLOW

BY : CHAM Development Team - M R Malin

FOR : Validation of Convection Discretisation Schemes

DATE : 1995 PHOENICS Version : 2.2

PROBLEM CONSIDERED: - The test case is 2d pure convection of scalar step in a prescribed recirculating velocity field.

- A step profile of a scalar enters a rectangular domain, and is then convected clockwise through 180 degrees before leaving the domain.

- This case was devised by Smith and Hutton [1982] so as to provide a searching test of numerical convection schemes.

- PHOENICS Library Case N104

EXACT SOLUTION:

- The step change should be convected by the recirculating flow so as to appear as a step change at the outlet.

CALCULATION DETAILS:

- Library case N104 prescribes the rotational velocity field, and performs calculations for the scalar field using 5 linear discretisation schemes and 9 non-linear discretisation schemes.

- The calculations employ a uniform mesh of 20 by 20 cells, and no grid refinement studies have been conducted.

- Solutions for selected schemes are presented below, and compared with the exact solution. 1. Scalar Convection, Velocity Vectors & Streamlines 2. Scalar Convection, Scalar Contours - Upwind Scheme 3. Scalar Convection, Scalar Contours - QUICK Scheme 4. Scalar Convection, Scalar Contours - SUPERBEE Scheme 5. Scalar Convection, Scalar Profile at Y=0 - Linear Schemes 6. Scalar Convection, Scalar Profile at Y=0 - Non-Linear Schemes