March 15, 2021 at 10:02 pmsugarl14Subscriber
I have a wave energy converter that I am modeling that consists of a flap that is hinged to the sea floor, only allowing rotation (see general idea below)March 16, 2021 at 12:24 amMarch 16, 2021 at 9:37 amRobAnsys EmployeeCheck you have the correct version of VS too, R18 was released in about 2017 so you'll want 2015 or earlier as an educated guess: we're typically using a VS version that's out when we start the coding cycle, because of differences in release cycles that means picking a version that's 2-3 version years older.March 16, 2021 at 2:26 pmsugarl14SubscriberThank you and for your responses.Let me back up a little bit and ask another question..Since my UDF is very simple (i.e. I'm only constraining the motion to be rotation about the Y-axis and specifying a damping value), could I just use an interpreted UDF instead of compiled UDF? Or even simpler, could I just utilize the Six DOF Properties tool in Fluent (see below) instead of using a UDF altogether?To reiterate, all I am trying to do is 3D model a wave energy converter (the inverted pendulum pictured above) that rotates only about the y-axis. I'd like to specify damping value (15,000 Nm/rad), and reference angle constraints (-30 to +30 degrees). I am looking for the simplest way to do this in dynamic meshing.Thank you again for your help!March 16, 2021 at 4:35 pmRobAnsys EmployeeThe interpreted UDFs don't allow all of the macros to be used. With out reading the manual, I can't remember if that includes the mesh motion ones: I'm fairly sure it does.March 16, 2021 at 6:20 pmYasserSelimaSubscriberDynamic mesh macros must be compiledMarch 22, 2021 at 7:16 pmsugarl14Subscriberand thank you both for your involvement with my question.nI was able to successfully load and compile the UDF. As I mentioned previously, my situation involves a pendulum-like motion. The point of rotation that I am interested in is at [0 0 -3.3] meters but the CG of the device is at [0 0 -1.28] meters. nSince I am very new to UDFs, how would I define the motion of the flap to rotate about its hinge at [0 0 -3.3] rather than at its CG at [0 0 -1.28]? Would I specify that in the UDF? If so, how should the code be typed?.March 22, 2021 at 8:09 pmYasserSelimaSubscribersearch the manual for SDOFO_CENTER_ROT, or something close, macro. This is to determine the center of rotation ... Also you need to restrict the motion to 1 dimension. There are three examples in the manual for SDOF .. look at themMarch 22, 2021 at 8:12 pmsugarl14SubscriberThank you. I have completed the part that only allows rotation about the y-axis, but I will look into the SDOF_CENTER_ROT macro and let you know if I run into any more issues. Thank you!March 22, 2021 at 8:13 pmYasserSelimaSubscribernLook at this thread ... case that is very close to yoursnhttps://forum.ansys.com/discussion/22364/define-sdof-properties#latestnMarch 22, 2021 at 8:31 pmsugarl14SubscriberThank you for the reply. So in this example from the thread link you posted:nSDOFO_CENTER_ROT(sdof_obj) = 6.0; /* only needed for one DOF rotation */nSDOFO_CENTER_ROT(sdof_obj) = 1.1938; /* only needed for one DOF rotation */nSDOFO_CENTER_ROT(sdof_obj) = 0.0; /* only needed for one DOF rotation */nnthe , , and  parts correlate to the X, Y, and Z direction?.Furthermore, the 6.0, 1.1938, and 0.0 value refer to the coordinates? (i.e. [6 1.1938 0] meters?)nMarch 22, 2021 at 8:46 pmYasserSelimaSubscriberI believe so, but check the manual nMarch 22, 2021 at 8:47 pmsugarl14SubscriberI couldn't find this in the manual for Fluent V 18.1. Is this macro only something for Fluent 2020 R2?nMarch 23, 2021 at 10:02 amRobAnsys EmployeeProbably not new to 2021R1 but we do expand the documentation with the release cycle so you can find older/newer versions have different examples and more/less macros explained. nMarch 23, 2021 at 1:00 pmsugarl14SubscriberHi Arraythank you for your response!nnSo does that mean the macro SDOFO_CENTER_ROT(sdof_obj) is or is not available in Fluent version 18.1?nMarch 23, 2021 at 1:41 pmRobAnsys EmployeeIt means it may not be in the documentation; I would be surprised if it wasn't in the code but without checking I don't know. What happens when you use it? Note, R18 is now around 5 years old so you really need to update to get the latest technology. nMarch 23, 2021 at 8:26 pmMarch 24, 2021 at 11:45 amRobAnsys EmployeeR18 would have had a local install of help. nMarch 29, 2021 at 8:37 pmsugarl14Subscriberand nThank you for your help. I will try this out and let you know if it works in R18. I was able to get ANSYS 2021 R1 also so if it does not work in R18 I'll move to version 2021nMarch 29, 2021 at 9:36 pmYasserSelimaSubscriberthis is taken from 2020 R2 manual ...nViewing 19 reply threads
Ansys Innovation Space
- You must be logged in to reply to this topic.
Earth Rescue – An Ansys Online Series
The climate crisis is here. But so is the human ingenuity to fight it. Earth Rescue reveals what visionary companies are doing today to engineer radical new ideas in the fight against climate change. Click here to watch the first episode.
Subscribe to the Ansys Blog to get great new content about the power of simulation delivered right to your email on a weekly basis. With content from Ansys experts, partners and customers you will learn about product development advances, thought leadership and trends and tips to better use Ansys tools. Sign up here.Trending discussions
- Suppress Fluent to open with GUI while performing in journal file
- Floating point exception in Fluent
- What are the differences between CFX and Fluent?
- Heat transfer coefficient
- Getting graph and tabular data from result in workbench mechanical
- The solver failed with a non-zero exit code of : 2
- Difference between K-epsilon and K-omega Turbulence Model
- Time Step Size and Courant Number
- Mesh Interfaces in ANSYS FLUENT
- error in cfd post
© 2023 Copyright ANSYS, Inc. All rights reserved.Ansys does not support the usage of unauthorized Ansys software. Please visit www.ansys.com to obtain an official distribution.