Example Entry Flow in a Pipe

Step 1 To solve this, enter FEMLAB and choose Chemical Engineering, Axisymmetric 2D/Momentum/Navier-Stokes/Stationary. In axisymmetric geometries, FEMLAB uses the horizontal axis as radius (called r) and the vertical axis as the length axis (called z). The corresponding velocity components are u in the radial direction and v in the axial direction. The sketch shows how the geometry is displayed. 

Step 2 Click on the rectangle or use the Draw menu, then rectangle. Put the cursor on a point and drag it to make a rectangle. If you double click on the rectangle, you can set the exact dimensions. Make the rectangle 0.5 x 2. 

Step 3 Choose Options/Axis/Grid Settings to set the screen dimensions so you can see the rectangle easily. In Options/Axis/Grid Setting is a box to force the axes to be equal if you like. 

Step 5 Choose Physics/Subdomain Settings and a window appears showing Eq. (10.10)  

Step 6 Choose Physics/Boundary Settings. Set the boundary conditions as follows  

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