[ccorvera]

Hi there,

I am running a simulation of a channel with a mainstream flow, intercepted by a flow of a high velocity jet at an angle. The jet impinges onto a heated surface, then both flows exit at the end of the channel. I am having a hard time getting Fluent to converge to 10e-6, with residuals converging to about 5e-4 and then oscillating about that value/

I have heard that oscillation could be due to inadequate inflation layers, so I increased the number of inflation layer elements on all surfaces, but I am still getting no convergence after many hours. Can anyone suggest any fixes?

The working fluid is air, modeled as an ideal gas, k-epsilon turbulence model, gravity enabled, and the SIMPLEC method (Coupled method does not come close).

Mainstream velocity is 10m/s (Re = 19,000; Ma = 0.03) and temperature is 303.15K.

Jet velocity is 50m/s (Re = 49,000; Ma = 0.14) and temperature is 303.15K. Jet intercepts main flow at 45 degree inclination.

Channel exit is given the "outlet vent" boundary condition.

A picture of the failed residuals is attached.

[telegrampay.eth]

why don´t you use pressure outlet rather than outlet vent?

Outlet vent boundary conditions are used to model an outlet vent with a specified loss coefficient.

[telegrampay.eth]

also it may be the mesh resolution problem. 1e-6 convergence may need very fine mesh

Originally Posted by ccorvera

Hi there,

I am running a simulation of a channel with a mainstream flow, intercepted by a flow of a high velocity jet at an angle. The jet impinges onto a heated surface, then both flows exit at the end of the channel. I am having a hard time getting Fluent to converge to 10e-6, with residuals converging to about 5e-4 and then oscillating about that value/

I have heard that oscillation could be due to inadequate inflation layers, so I increased the number of inflation layer elements on all surfaces, but I am still getting no convergence after many hours. Can anyone suggest any fixes?

The working fluid is air, modeled as an ideal gas, k-epsilon turbulence model, gravity enabled, and the SIMPLEC method (Coupled method does not come close).

Mainstream velocity is 10m/s (Re = 19,000; Ma = 0.03) and temperature is 303.15K.

Jet velocity is 50m/s (Re = 49,000; Ma = 0.14) and temperature is 303.15K. Jet intercepts main flow at 45 degree inclination.

Channel exit is given the "outlet vent" boundary condition.

A picture of the failed residuals is attached.

[LoGaL]

If anything, finer mesh hampers convergence, doesn't improve it xD.

Can we see the flow field? Maybe it's just that it doesn't find a steady state solution... Can sometimes be possible. I would anyways stick to the coupled method.