November 8, 2023 at 1:37 pmjasonsum25Subscriber
I am setting up a transient simulation modelling the air flowing through a single stage tesla valve for learning its flow physics.
Setup: k-omega SST model, PISO algorithm with 2nd order upwind
B.C.: pressure inlet of 1000 Pa total pressure and pressure outlet of 0 Pa gauge pressure - the delta p driving the air flow across the valve
Apart from viewing velocity and pressure contour plots, I want to straightly identify air entering without including the air originally staying in the cell zone, so that I can track how the incoming air develops along the winding paths (as if tracing flow with ink in real life experiments)
I tried to set up a User Defined Scalar and set such scalar in the inlet as 1, yet the result did not look like a tranisent air scalar behavior. Therefore I am not sure is it the right way to do so. (animation screen cap attached below)
The visualised result I want is something like this below (reference from Holzman CFD Youtube video):
It is sincerely hoped for help! Thanks so much!
November 8, 2023 at 4:39 pmRobForum Moderator
That looks like the flow didn't develop very well. Can you post the velocity contour so we can see what's going on? As an aside the angle and shape of these sorts of valves is very important, small deviations can have significant effects on the results: power fluidic devices use this to control flow.
November 10, 2023 at 5:32 pmjasonsum25Subscriber
My trial on this T45 single-stage tesla valve is just for myself to understand the flow physics behind when there is pressure difference driving the inflow.
Below are result of transient velocity and pressure contour plots under convergence:
My concern is, the passive scalar of incoming air shown in previous comment gradually filling up the valve, but not similar to the result from the Holzman CFD Youtube video (only "concentration/portion" of incoming air tracing). I would like to know is sth wrong about my setup of UDS. Thank you!
November 14, 2023 at 3:07 pmRobForum Moderator
Is this for water, and what is the scalar diffusivity?
November 14, 2023 at 4:58 pmjasonsum25Subscriber
It is air flowing from inlet of the valve (single phase). I set scalar diffusivity as 1, following some online videos on setting, not sure if it is not making sense. I would like to know the way to obtain the visualised result like the one from Holzman CFD Youtube video as shown above. Thanks for the guidance!!!
November 14, 2023 at 5:11 pmRobForum Moderator
Ah, that'll explain it. The scalar is diffusing far too much. Treat the scalar like a species, and divide the typical value for that species diffusivity by the fluid density (scalars don't really have units). Liquids will be diffusivity of 1e-9 to 1e-10 or so - look it up as I usually have to.
- You must be logged in to reply to this topic.
Boost Ansys Fluent Simulations with AWS
Computational Fluid Dynamics (CFD) helps engineers design products in which the flow of fluid components is a significant challenge. These different use cases often require large complex models to solve on a traditional workstation. Click here to join this event to learn how to leverage Ansys Fluids on the cloud, thanks to Ansys Gateway powered by AWS.
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.
- legend min and max
- Ensight hot iron palette from an image
- Streamlines in EnSight using MRI data
- Import MRI data into Ensight
- FLUENT APPLICATIION ERROR
- Total Surface Heat Flux Calculation in Fluent
- Difference between “total pressure” and “absolute pressure”?
- Drop Test of a Water-Filled Tube
- Minimum Orthogonal Quality Less than 0.01 For Transonic Airfoil Flow Analysis
- obtaining pressure distribution by making points in ansys
© 2023 Copyright ANSYS, Inc. All rights reserved.