Why back flow at the outlet???
 

Hi to every one,

I am trying to simulate the diesel flow in the nozzle of the injector. At the outlet of the nozzle i am getting the back flow. I have used the following boundary condition for velocity and pressure.

0/p file

INLET3
{
type totalPressure;
U U;
phi phi;
rho none;
psi none;
gamma 1;
p0 uniform 1100000;
value uniform 1100000;
}
OUTLET4
{
type fixedMeanValue;
meanValue 100000;

}

}


0/U file

INLET3
{
type zeroGradient;
}
OUTLET4
{
type inletOutlet;
inletValue uniform (0 0 0);
value uniform (0 0 0);



So could you please tell me the reason why there is back flow at the outlet of the nozzle.???


Thanks in advance.