[Raffaele S]

Hello everybody, I am a master's Student and I'm trying to simulate for my thesis project the motion of a cell inside a confined channel in 2D geometry. The dimensions are:
H = 21 um
Cell's diameter = 20um
Length= 100 um.
The viscous model is set as laminar because the Reynolds number is very low, there is no velocity in the inlet and the pressure outlet is imposed equal to zero (gauge pressure = 0 [Pa]).
I supposed that the cell is a simple circle and in the Name selections I defined the boundary of the object as "object wall".
I used a UDF to impose the motion of the cell ("object wall") as unidirectional with a velocity of 0.2 um/s. The project aims to analyse the pressure gradient generated by the cell in this geometry during its motion. There are no errors, but the results in the pressure gradient appear very weird; the simulation is a transient one, so I inserted my UDF file in the dynamic mesh zones imposing the movement of the object wall.
The UDF code is the following one:
#include "udf.h"

DEFINE_CG_MOTION(moving_particle,dt,vel,omega,time ,dtime)
{
real t = CURRENT_TIME;
NV_S (vel, = , 0.0);
NV_S (omega,= , 0.0);

vel[0] = 0.0000002;
vel[1] = 0.0;


}
Below, you can observe two different pictures taken from the Results, one image describes the static pressure using the global scale and the other one describe the same simulation with different maximum and minimum value in the scale bar.
https://files.fm/u/x239mac52



The scale bar is changed from global to user-specified (0 [Pa] - 7e-7 [Pa]):
https://files.fm/u/vgspb7tdc


Thanks a lot, any advice is strongly appreciated