{"id":387541,"date":"2024-09-30T14:43:14","date_gmt":"2024-09-30T14:43:14","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/ansys-aqwa-questions-on-froude-scaling\/"},"modified":"2024-10-01T09:08:24","modified_gmt":"2024-10-01T09:08:24","slug":"ansys-aqwa-questions-on-froude-scaling","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/ansys-aqwa-questions-on-froude-scaling\/","title":{"rendered":"ANSYS AQWA – Questions on Froude Scaling"},"content":{"rendered":"

<p>Hi,<\/p><p>I am trying to understand how the Froude scaling would work in AQWA for a single floating cuboidal strucutre with 4 mooring lines with regular waves (2nd order stokes) as shown in the figure below.<\/p><p><\/p><p>So what I am trying to do is to scale this model DOWN by a factor of 10 and then to compare the RAOs to ensure that the values remain the same. The process I followed is as follows:<\/p><\/p>\n

    \n
  1. I used the Froude’s law of scaling to scale the entire system down by a factor of 10. This scaling was applied to the geometry, mooring lines and for the wave properties. The values can be seen in the image below.<\/li>\n
  2. Only the results from the hydrodynamic response analysis were considered for this study (as HD does not include mooring line stiffness). The actual responses from the HR analysis was used to calculate the pitch RAO using the equation as shown in the image below<\/li>\n<\/ol>\n

    <p>From the above image it can be seen that the RAOs from both the full scale prototype (RAO_fullscale = 1.57 deg\/m) and the scaled down model (RAO_scaledDown = 13.97 deg\/m) are extremly different. I am not able to understand where I am going wrong as I feel I have scaled everything correctly.<\/p><p>Also, I observed that the equation I have used to calculate the RAO might not be correct as from the time series plot of pitch response from the above image, the response is not periodic and keeps varying with time.<\/p><p>Please let me know on how to correct this.<\/p><p>Thanks!<\/p><\/p>\n","protected":false},"template":"","class_list":["post-387541","topic","type-topic","status-publish","hentry"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t