Solving the World’s Toughest CFD Problems

# Optimizing Design Performance with Baffle Placement

## Optimization Goal

Slosh damping in liquid storage tank with baffles

## Optimization Challenge

Generate a workflow that allows a user to run multiple iterations of a sloshing simulation to find the optimal ring baffle position that maximizes damping in a large, cylindrical tank. The case simulated here is based on the physical experiment by Maleki and Ziyaeifar (2008)1.

## Optimization Solution

The simulation represents the free decay of sloshing in fluid that is initially oriented 5 degrees from horizontal at a fluid height of 0.6 m in a vertically oriented cylindrical tank. The position of the ring baffle can translate in the z-direction. The objective is to find the location of the baffle that results in the greatest amount of slosh damping. Each simulation runs approximately ten minutes on 12 CPU cores.

A budget, or number of simulation iterations allowed, of 30 iterations is specified. FLOW-3D (x) runs 30 simulations to generate a response surface which represents the behavior of the system. This allows the best solution to be found.

## FLOW-3D (x) Workflow

FLOW-3D (x) uses nodes to construct automated workflows for the optimization. At the start of this workflow an initial baffle location in the z-direction is given. The baffle location is then allowed to translate vertically between prescribed bounds. Each simulation is then fed into a FLOW-3D node that executes iterative simulations. The results from the simulation are then connected into a calculator node that performs the damping calculation. The optimization engine will then choose another z coordinate of baffle based on the ever-improving response surface and continue with another simulation run.

## Results

Using FLOW-3D (x)’s built-in data analysis tools, a graphical representation of results immediately reveals that a baffle height of 0.55m provides the maximum damping ratio. The simulations and iterative design features are all automated with the program. Additionally, images and videos of each individual simulation can be set to output.

### References

1Maleki, A. and Ziyaeifar, M., 2008. Sloshing damping in cylindrical liquid storage tanks with baffles. Journal of Sound and Vibration, 311(1-2), pp.372-385.