I’m trying to simulate a propeller disk, as in the momentum theory.
I’m a bit unclear about how to set the boundary layer of my disk to represent the energy imparted from the propeller to the air, as it will break the conservation of laws as represented by NS equation.
project link: [Deleted by author]
Also my geometry surface splitting operation failed for some reason.
You can have a look at public projects for propellers and you can see that only the propellers themselves are refined with inflated boundary layer cells and not the cylinder which is only used for the rotating zone (MRF). If you cannot find the example let me know and I will help you out!
I don’t think you got the gist of what I’m trying to get. There is no actual blade or propeller. In momentum theory, the propeller is modelled as a simple disk imparting energy as a pressure increase on the flow. As this energy is externally applied, it breaks the conservation of momentum of air crossing the disk.
looked up the actuator disk case and now know what it is about, quite interesting! Will have to skim the documents and papers I can find and see if there needs to be a special BC implemented for this case and if not I can help you to validate the results from Mikkelsen (2003) - guess that’s what you are trying to do, right?
have not given it a try yet, did you? Can you tell me the measurements of your actuator disk? I will then start a first run and we can see if my simulation fits your expectations.
here is the first sim which is still running though. Also initialized with small values. Can you then try adapting it for your purposes? Project: Actuator Disk - Simulation
Here a simulation with 1 \frac{m}{s} freestream velocity and 5 \frac{m}{s} from the fan. You can play around with it and see if you can validate the results from the paper. Also I have just taken an estimate depth (y-coordinate) for the fan and have not adapted every numerical setting like in the document - actually one time I had an error and simply set back the settings for the velocity.
I have trouble understanding what you did. As far as I understand the Part 1 is the domain, but how did you add the Cylinder 1? Also I cannot find where are the settings for the cylinder, the boundary conditions are for the domain only.
First about the cylinder settings and the “missing” boundary conditions. Momentum sources can be used to simulate fans, ventilators and other similar devices. Whilst normally, the user would have to provide a detailed geometry and a fine mesh of these components, this feature allows one to define a volume which generates momentum, without any further complication.
\underline{\textbf{1. Create the box with OnShape}}
I ignored the recommendations from the paper in the beginning and just created a bigger domain by intuition. Feel free to follow the paper and see if the size has an influence.