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Topics - moloy_kb

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1
Fluent / Time dependent source term
« on: September 06, 2012, 06:44:11 AM »
Dear all,

I am trying to solve the effect of body acceleration on the human arterial system. For that I need to write some codes for a time dependent source term in DEFINE_SOURCE Macros. The acceleration term is given by
a(t) = a0*Cos(omega*t+Phi), where a0 is the amplitude part of the acceleration in mm, but the Fluent document tells that the dimension of the source term should be in N/m^3. How to make the proper dimension for the problem.

2
Fluent / moving wall problem
« on: August 24, 2012, 08:31:49 AM »
Dear all,
I want to simulate the flow through a pipe in Fluent whose wall is moving in sinusoidal manner along normal direction. Please help me in this regard. I am also attaching the geometry of the problem.

3
Fluent / Porous media in Fluent
« on: July 12, 2012, 11:04:05 AM »
Dear all..
Please find the attached document, where I clearly mentioned about the problem that I am facing regarding the formulation of the problem.
Any help is highly appreciated.

4
Fluent / non newtonian viscosity problem
« on: June 27, 2012, 11:23:50 AM »
Dear all,
I am simulating the problem of blood flow through an artery in 2D considering laminar flow. For this I am using the Walburn and Scneck model to define the blood viscosity using the equation:
mu_lam=K*(strain)^(n-1), where K=14.67*10^(-3) and n=0.7755. In order to define the viscosity I am using the following UDF:
#include "udf.h"
DEFINE_PROPERTY(cell_viscosity_power_law,c,t)
{
double mu_lam;
double strain;
double muinf = 14.67e-3;
double n = .7755;
strain = pow(C_DUDX(c, t),2)+ pow(C_DVDY(c, t),2)+
2*pow(C_DUDY(c, t)+ C_DVDX(c, t),2)+
2*pow(C_DUDZ(c, t),2)+
2*pow(C_DVDZ(c, t),2);
strain = pow(strain, 0.5);
strain =fabs(strain);
mu_lam=muinf*pow(strain,n-1);
return mu_lam;
}
But, once I try to solve it the solver gives the error: Divergence detected in the AMG solver.
Please help me...

5
Fluent / Outlet Boundary condition
« on: June 08, 2012, 07:46:50 AM »
Dear all,
I am simulating the laminar flow through a pipe having one(1) inlet and ten(10) outlets. As a boundary condition I am prescribing the inlet velocity for the inlet plane. For the outlets, I know the value of outflow discharges as a percentage of the inlet flow like

Inlet:100%       outlet1: 20%
                      outlet2:5%
                     outlet3:10%
                     outlet4:5%
                     outlet5:11%
.....
But, how to put this boundary condition in Fluent.

6
Fluent / Particle injection in DPM
« on: May 29, 2012, 07:32:48 AM »
Dear all,
I am doing the unsteady DPM calculation and there I want to inject particle in the domain at every alternate particle time step. How to do it??

7
Fluent / Particle Plot
« on: April 27, 2012, 05:06:01 AM »
I am doing DPM to track the particle on the wall of a 3D pipe. How to plot the location of the trapped particle only on the surface of a pipe?

8
Fluent / Histogram plot in DPM
« on: April 27, 2012, 05:03:32 AM »
Dear All,
I am doing one unsteady particle tracking using transient flow. For analysis of particles that are trapped in the target zone, i open the sample file and plot the histogram. The result gives quite satisfactory when we plot all the x-loc of the trapped particle in the histogram. But when I plot the time variable histogram, the plot is not quite understandable.
If anybody worked on this please explain the meaning of time variable in the dpm histogram sample file variable list.

9
Meshing / conv-div nozzle geometry
« on: April 07, 2012, 10:40:53 AM »
Hi,
How to draw the convergent divergent shaped nozzle, in which the variation of area is given by A=0.1+2.58x^2, using Ansys 13 Design Modeller.
Pl. reply

10
Fluent / Unsteady flow and DPM
« on: March 17, 2012, 10:46:10 AM »
I want to study the behavior of the particle under the unsteady flow. Consider a situation where the flow through a pipe in pulsatile in nature, say at the inlet to the pipe, the velocity is given as V=V_0*(1+sin(w*t)). If I solve the unsteady Fluent Solver, it will give the result, but what happens if I wants to solve the DPM along with this.
For, steady flow like V=V_0, first the eulerian flow field has to be solved, then we switch on  the DPM. Now, how to implement this in case of pulsatile problem.
Thanks in advance.

11
Fluent / DPM in FLUENT
« on: March 14, 2012, 05:24:09 AM »
Hi,
I want to calculate the particle interaction force using DPM. For this force calculation I have to know the position of each and every particle at any particular step. Suppose I want to calculate the force on 'P' th particle, then that force is dependent on position of each particle, like
Force_on-Pth_part=Function(Position-part1+Position-part-2+.....+Position-part-N), where we assume that there are 'N' no of particles are injected.
The entire calculation has to be repeated for each particle that are being tracked.
Please help me in this regard.

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