Hydrodynamic Pressure Setup for Gravity Dam in ANSYS Workbench

[earandamunoz]

Hello,

I am currently working on a gravity dam model in ANSYS Workbench using modal and transient structural analysis, where earthquake acceleration is applied in X, Y, and Z directions.

The main issue I am having is how to correctly include hydrodynamic pressure from the reservoir during the earthquake.

At first, I used the Westergaard equation to create a pressure profile on the upstream face of the dam based on water depth. Later, after discussing with my advisor, we realized that this pressure only changes with depth and does not directly include time, so we were unsure if it should really be considered dynamic pressure.

To try to improve this, I entered the pressure in transient structural as tabular data, where the pressure changes over time using the earthquake acceleration record.

Right now, I have:

• base acceleration applied in three directions

• pressure applied on the upstream face in transient structural

• pressure varying with time through tabular input

My main concern is whether this is a reasonable way to approximate hydrodynamic pressure, or if I may be applying something incorrectly.

I also tried using the hydrodynamic diffraction tools in Workbench, but that did not go far because it kept asking for AQWA files, which I do not currently have.

I would appreciate guidance on:

2. Whether using transient pressure this way is acceptable for hydrodynamic pressure

3. Whether this could duplicate effects already included through base acceleration

4. What the recommended approach would be when only earthquake acceleration data is available

I am still learning ANSYS Workbench as part of my graduate research and teaching myself much of the software, so any guidance or suggestions would be greatly appreciated if I am approaching this incorrectly. Thank you for any advice.

[Rob]

I suspect you need to ask this in the Structures/Mechanical section. 

AQWA is more useful for mooring/floating analysis, and Fluent (CFD) would be for when the dam bursts and you want detailed knowledge of where the water is going.