# Shear Flow

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Hello every one.

I need help. How to generate shear flow at velocity inlet & nodal initial condition at AcuSolve (as attach picture).  For now, i only want to simulate shear flow in empty domain. After shear flow successfully generate, i want to put riser in the domain.

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Let's assume the flow direction is X (right to left in your picture) and the vertical direction is Z (bottom to top in your picture).  In Nodal Boundary Condition, variable is x-velocity, type is piecewise-linear.  Curve-fit-variable is z-coordinate - then enter the values (table) for x-velocity as a function of z-coordinate.  Should be similar for Nodal Initial Condition.  This will give the same profile everywhere - no difference for the side and top walls.

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12 hours ago, acupro said:

Let's assume the flow direction is X (right to left in your picture) and the vertical direction is Z (bottom to top in your picture).  In Nodal Boundary Condition, variable is x-velocity, type is piecewise-linear.  Curve-fit-variable is z-coordinate - then enter the values (table) for x-velocity as a function of z-coordinate.  Should be similar for Nodal Initial Condition.  This will give the same profile everywhere - no difference for the side and top walls.

Dear Acupro,

i have tried the solution you provided but still, unsuccessful.

at nodal initial condition, i need to use script instead of built in table at nodal boundary condition.

Is it possible for u to fix my mistake using my .acs file as attach?

my domain as follow:

X Min/Max: -20.0  20.0
Y Min/Max: -10.0  -10.0
Z Min/Max: -20.0  0.0

flow direction: positive x

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1.  For the inlet NBC, you may want to use cubic-spline rather than linear.  It depends on if you want linear or cubic interpolation between your given data points.

2.  For the NIC, you have two choices, since piecewise linear is not available in AcuConsole.  You can either use a tool like Excel to determine the equation for the velocity based on Z - and use 'Script' in AcuConsole.  Or you'll need to edit the input file once written, and use piecewise-linear (or cubic spline), as described in the Command Reference Manual under Nodal Data Commands > Nodal Initial Condition, which will then be similar to the NBC.

Dear AcuPro,

Its working!!!

TQVM!

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