Flow Over a Rotating Bridge CFD

[NazD]

Hi everyone,

This is my first post as I am a new member here.

I am trying to simulate an opening of a bascule bridge and study the flow over it in Fluent. I simplified the problem by allowing the bridge to be represented by a flat plate and I used Reynold's Number scaling to scale my dimension and wind velocity.

My objective is to create a 2D, transient, Fluent study in which the "bridge" rotates -at one end - to an angle of approximately 60 degrees.

I am having issues in creating the geometry and setting up the rotating body in fluent.

As seen in the figures below, I created an enclosure with a velocity inlet (left) and a pressure outlet (right). I used boolean to subtract the rotating body from the enclosure and another boolean to subtract the plate from the rotating body. I then used mesh motion in fluent to rotate the rotating body about it's center. The problem I am having is the fact that this geometry does not relate to the physical situation. More specifically, the roadway has to extend further into the rotating body and up to the beginning of the bridge so that the flow does not travel underneath the bridge. But because of the boolean, that portion of the roadway gets removed. I tried to solve this by removing one of the booleans and re-running the simulation, however, the flow would just go through the plate as if it was not even there.

Does anyone have an idea of what I can try?

Thank you for your input

 

[Achy47]

!

Hello,

As a fellow scientist, I understand the challenges you are facing in creating a realistic simulation of the bascule bridge opening. Based on your description and figures, it seems like your current geometry is not accurately representing the physical situation, leading to incorrect flow behavior.

One solution you could try is to create a separate geometry for the roadway and the bridge, and then use the "mesh interface" feature in Fluent to connect the two geometries. This will allow for a more accurate representation of the flow around the bridge and the roadway without any boolean operations.

Another option is to use a "sliding mesh" approach, where you create a mesh for the stationary part of the bridge and a separate mesh for the rotating part, and then use the "mesh motion" feature to simulate the rotation of the bridge. This approach may require some additional effort in meshing, but it will provide a more accurate representation of the flow.

I hope these suggestions help you in your simulation. Good luck!