Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

HD: Bug fix for potential-flow wave excitation with multiple bodies and large yaw offset #2408

Merged
merged 1 commit into from
Sep 9, 2024

Conversation

luwang00
Copy link
Contributor

@luwang00 luwang00 commented Sep 7, 2024

Feature or improvement description
Two bugs were identified that led to incorrect potential-flow wave excitation when multiple bodies are present with large yaw offset (PtfmRefY!=0 or PtfmYMod=1):

  • When NBodyMod=1 and NBody>1, only the wave excitation on the first body is transformed back to the inertial frame. This PR adds the transformation of the subsequent bodies.

  • When PtfmRefxt!=0 or PtfmRefyt!=0, there is effectively a displacement of each potential-flow body due to platform yaw offset when precomputing the wave excitation. In other words, the effect of this baseline displacement is already baked into the precomputed wave excitation, so it needs to be subtracted from the total body displacement when interpolating the wave excitation if ExctnDisp>0. This correction is implemented in this PR.

Impacted areas of the software
HydroDyn

Test results, if applicable
Existing tests are not impacted by the bugs identified, so no change to the test results.

…nd large yaw offset

Two bugs are identified that lead to incorrect potential-flow wave excitation when multiple bodies are present with large yaw offset (PtfmRefY!=0):
* When NBodyMod=1 and NBody>1, only the wave excitation on the first body is transformed back to the inertial frame in WAMIT_Init.
* When PtfmRefY!=0 with PtfmRefxt or PtfmRefyt being nonzero, there is effectively a displacement of each potential-flow body due to platform yaw offset when precomputing the wave excitation each body. In other words, the effect of this baseline displacement is already baked into the precomputed wave excitation, so it needs to be subtracted from the total body displacement when interpolating the wave excitation in WAMIT_CalcOutput if ExctnDisp>0.
Copy link
Collaborator

@andrew-platt andrew-platt left a comment

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I don't know all the details in your transform, but this looks correct.

@andrew-platt
Copy link
Collaborator

Related to #2203

@andrew-platt andrew-platt merged commit 2246bef into OpenFAST:dev Sep 9, 2024
21 checks passed
@luwang00 luwang00 deleted the b/HD_NBody_LrgYaw branch September 9, 2024 18:37
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Projects
None yet
Development

Successfully merging this pull request may close these issues.

2 participants