# Tesla Micromixer CFD simulation troubleshooting - incorrect results and distribution **URL:** \ **Category:** Fluid Flow / CFD\ **Created:** [July 17, 2026, 4:08pm UTC](https://www.simscale.com/forum/t/tesla-micromixer-cfd-simulation-troubleshooting-incorrect-results-and-distribution/101218 "2026-07-17T16:08:02Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![Karakat](https://www.simscale.com/forum/letter_avatar/karakat/32/6_22734026db12803ebb3e059622ac3534.png) [@Karakat](https://www.simscale.com/forum/u/Karakat)\ **Post date:** [July 17, 2026, 4:08pm UTC](https://www.simscale.com/forum/t/tesla-micromixer-cfd-simulation-troubleshooting-incorrect-results-and-distribution/101218/1 "2026-07-17T16:08:02Z")
Hello, I am working on a Tesla Micromixer simulation using the Incompressible CFD solver. I have set up everything, but the simulation results in **Run 2** look completely incorrect. The contour plots for the **Passive Scalar 1** , velocity, and pressure do not look right. Almost the entire channel remains blue, and there is no proper mixing or fluid distribution showing from the inlet. I suspect there is a mistake somewhere in my general settings, boundary conditions, or numerical controls, but I can’t figure out where. Could someone from the community or support team please look into my project and guide me on what exactly is wrong with my setup? Here is the link to my project: [SimScale Login](https://www.simscale.com/workbench/?pid=4724248555628394610&rru=61d51a46-4d54-448f-90b3-08f30189d975&ci=82c231b1-0423-4640-b289-3fa879c11c35&mt=SIMULATION_RESULT&ct=SOLUTION_FIELD) Thank you in advance! ---
**Author:** ![mscholler](https://www.simscale.com/forum/letter_avatar/mscholler/32/6_22734026db12803ebb3e059622ac3534.png) [@mscholler](https://www.simscale.com/forum/u/mscholler)\ **Post date:** [July 21, 2026, 8:55am UTC](https://www.simscale.com/forum/t/tesla-micromixer-cfd-simulation-troubleshooting-incorrect-results-and-distribution/101218/3 "2026-07-21T08:55:32Z")
> [@Karakat](#): > > city, and pressure do not look right. Almost the entire channel remains blue, and there is no proper mixing or fluid distribution showing from the inlet. I suspect there is a mistake somewhere in my general settings, boundary conditions, or numerical controls, but I can’t figure out where. > > Could someone from the community or support team please look into my project and guide me on what exactly is wrong with my setup? > > Here is the link to my project: [SimScale Login](https://www.simscale.com/workbench/?pid=4724248555628394610&rru=61d51a46-4d54-448f-90b3-08f30189d975&ci=82c231b1-0423-4640-b289-3fa879c11c35&mt=SIMULATION_RESULT&ct=SOLUTION_FIELD) Hi Karat, looks like that it havent run for a suffucient number of iterations/timestep… ---
**Author:** ![Karakat](https://www.simscale.com/forum/letter_avatar/karakat/32/6_22734026db12803ebb3e059622ac3534.png) [@Karakat](https://www.simscale.com/forum/u/Karakat)\ **Post date:** [July 25, 2026, 7:33am UTC](https://www.simscale.com/forum/t/tesla-micromixer-cfd-simulation-troubleshooting-incorrect-results-and-distribution/101218/4 "2026-07-25T07:33:11Z")
Hi! Following your advice, I increased the number of iterations to 3,000 and the timestep size to around 200. It got a little better, but the mixing is very sharp at the beginning, and by the end, everything remains blue (unchanged). ---
**Author:** ![BryanArsenio](https://www.simscale.com/forum/user_avatar/www.simscale.com/bryanarsenio/32/71634_2.png) [@BryanArsenio](https://www.simscale.com/forum/u/BryanArsenio)\ **Post date:** [September 24, 2026, 6:45pm UTC](https://www.simscale.com/forum/t/tesla-micromixer-cfd-simulation-troubleshooting-incorrect-results-and-distribution/101218/6 "2026-09-24T18:45:53Z")
Hi @Karakat, The number of iterations/timesteps could certainly be part of the issue, as mentioned above. I also checked the project you shared, and I would suggest reviewing the **passive scalar setup and initialization** before only increasing the runtime. In particular, please check that: - the two inlets have the intended scalar values, for example 1 and 0, - the initial scalar value in the domain is set appropriately, and - the velocity field is sufficiently developed before evaluating the scalar distribution. If the scalar and flow initialization are correct, then increasing the simulation time would be the next thing I would check. Thanks! Bryan