DPM modelling

Member
edited October 16 in Fluids

I'm facing a problem in ANSYS Fluent simulation DPM rain modelling in which rain droplets are injecting from the inlet and top surface but I'm not getting the results as expected.

The detail information of my problem is attached with this discussion. Can anyone help me to figure out the problem?

• UKForum Coordinator

Staff are not permitted to open or download attachments. I assume gravity is on, and defined in the correct direction? Eg is z+ is up gravity is -9.81 m/s/s.

• Member

Yes, it's defined in correct direction.

I'm specifying the whole problem definition as follows since as you told me staff are not permitted to open or download the attachments.

Definition:

We are trying to estimate the effect of rain on aerodynamic performance of Ahmed body. Flow around the Ahmed body is a well-known benchmark test cases used by the computational fluid dynamics (CFD) community for model validations for automobile.

We have setup everything in ANSYS Fluent and all the setup that we specified are as follows.

Step 1: Mesh Setup

You can see the mesh of the model and domain which contains 7.6 million elements in the picture.

Step 2: DPM Setup

Following is the setup that we used to inject water particle from inlet and top surface.

Problem:

The mass flow rate for DPM at the inlet and top surfaces were specified based on the rain intensity of 19 g/m^3. We expected to see a uniform rain intensity of 19 g/m^3 in the computation domain away from the body. However, the results showed the particle mass concentration is almost zero in front of the body (see the figure below). Any idea why it’s not showing patches with zero rain intensity? The patch with zero rain intensity at the back is reasonable, based on the flow characteristics. However, there should not be any patch with zero rain in the front and top.

• Member

and here is the mass concentration result that we got.

• UKForum Coordinator

Can you plot where the particles are? I'm wondering if you have droplets throughout the refined region.

• Member

I'm not able to track the particle. It requires some file to upload it.

• Member

Any other guess why it's creating problems?