[Md Nabil]

Hello,

I wanted to know if I can obtain the shear rate of particles (30 microns) while they flow in a channel. I am using the DPM model for simulation in Ansys Fluent. All I got from the internet is how to obtain the shear stress of fluid. But if there is a way to obtain the shear stress and rate of the particles suspended, that would be really helpful to me.

[Md Nabil]

As it turned out the UDF below worked for me

#include "udf.h"
#include "dpm.h"

DEFINE_DPM_DRAG(spherical_drag_shear_velocity_mode l, Re, p)
{
real mu, dp, v_rel, drag_force, shear_stress, particle_area, particle_velocity;

cell_t c = P_CELL(p);
Thread *t = P_CELL_THREAD(p);

mu = C_MU_L(c, t); // dynamic viscosity in this cell

dp = P_DIAM(p);

particle_velocity = sqrt(pow(P_VEL(p)[0], 2) +
pow(P_VEL(p)[1], 2) +
pow(P_VEL(p)[2], 2));

v_rel = sqrt(pow(P_VEL(p)[0] - C_U(c, t), 2) +
pow(P_VEL(p)[1] - C_V(c, t), 2) +
pow(P_VEL(p)[2] - C_W(c, t), 2));

drag_force = 3.0 * M_PI * mu * dp * v_rel;

particle_area = 0.25 * M_PI * pow(dp, 2.0);

shear_stress = drag_force / particle_area;

C_UDMI(c, t, 0) = drag_force;

C_UDMI(c, t, 1) = shear_stress;

C_UDMI(c, t, 2) = particle_velocity;

Message("drag force : %.10f\n", C_UDMI(c, t, 0));
Message("shear stress: %.6f\n", C_UDMI(c, t, 1));
Message("particle velocity : %.6f\n", C_UDMI(c, t, 2));


return drag_force;
}

But Report>Discrete Phase>Sample also works for velocity collection