**Title:** IAHR Smooth Channel Test Case

**By:** S Semin - CHAM Development Team

**Purpose of the Calculations:**

- The problem considered is 2-dimensional, steady, laminar, isothermal flow in the geometry devised by the IAHR Working Group on Refined Modeling of Flows. Results are reported in the article "Laminar Flow in a Complex Geometry: A Comparison" in the International Journal for Numerical Methods in Fluids, Vol. 5, 667-683 (1985).
- The main objective of the calculations is to validate the Generalised Colocated Velocity (GCV) solver.
- The solutions are compared with those of Cliffe et al., cited and used in the above reference as a grid-independent benchmark.

**Flow and Computational Details:**

The main features of the problem are:

- Laminar flow, Re = 10.0
- The North and South boundaries of the channel are given by the following analytical expression :

y(x) = +/- [tanh(2 - 30*x/Re) - tanh(2)]/2 for 0 ≤ x ≤ Re/3

- A parabolic profile for the axial velocity is specified at the inlet (shifted by -1 in comparison to the IAHR reference),

u = (3/2)*(1 - y*y) for x = 0 and -1 ≤ y ≤ 1,

v = 0.

- A mesh of 64 cross-stream cells by 32 axial cells is used for a computational domain length of Re/3.

This setup is available in PHOENICS' case library as Case B580.

**The following images show:**

The grid

The velocity field

The pressure field

Comparison of surface pressure for Re = 10

Comparison of surface pressure for Re = 100