# Project support **URL:** \ **Category:** Project Support\ **Created:** [December 23, 2021, 6:44pm UTC](https://www.simscale.com/forum/t/project-support/94763 "2021-12-23T18:44:30Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![ss02150](https://www.simscale.com/forum/letter_avatar/ss02150/32/6_22734026db12803ebb3e059622ac3534.png) [@ss02150](https://www.simscale.com/forum/u/ss02150)\ **Post date:** [December 23, 2021, 6:44pm UTC](https://www.simscale.com/forum/t/project-support/94763/1 "2021-12-23T18:44:30Z")
I have been trying for some time to set up a simulation that resembles that of the study conducted by a member of the Sim Scale team located [here](https://www.simscale.com/workbench/?pid=5821619361410420376&mi=spec%3A95a071e3-d699-4d3c-815d-2e11be470db5%2Cservice%3ASIMULATION%2Cstrategy%3A19). I am relatively new to using CFD and have received really good and helpful advice which i am very grateful for. I have tried my best to replicate the analysis conducted by @dlynch in the paper previously linked but I am unsure on how i can verify if my results are valid when compared (i understand it will not be exact). I have looked into checking my mesh quality and all seems good to me, when i compare the results for the forces and moments for the base point i have set they do not perfectly match when considering forces and moment in XYZ, in fact some values are not similar and off by magnitudes of 10. I would really appreciate it if someone could take a look and provide me with useful information on how to improve my work so far. Project located [here](https://www.simscale.com/workbench/?pid=4228370608098992886&mi=spec%3A93fd962c-19b7-47b5-b97f-173e32e80f42%2Cservice%3ASIMULATION%2Cstrategy%3A93&ps=analysis%2FinitialConditions%2FturbulentKineticEnergy) I have wasted many hours of computational time trying to resolve issues my self and have now admitted defeat. Thank you in advance Sam ---
**Author:** ![ggiraldof](https://www.simscale.com/forum/user_avatar/www.simscale.com/ggiraldof/32/30298_2.png) [@ggiraldof](https://www.simscale.com/forum/u/ggiraldof)\ **Post date:** [December 23, 2021, 7:41pm UTC](https://www.simscale.com/forum/t/project-support/94763/2 "2021-12-23T19:41:17Z")
Hey there! Two things come immediately to my attention: 1. Your flow region is too small, which causes the walls to be too close to the building. I would leave the space of 3 heights at the top, sides and upwind and 10 downstream. 2. Your ABL definition is strange, shouldn’t it just vary with the height? ---
**Author:** ![ss02150](https://www.simscale.com/forum/letter_avatar/ss02150/32/6_22734026db12803ebb3e059622ac3534.png) [@ss02150](https://www.simscale.com/forum/u/ss02150)\ **Post date:** [December 27, 2021, 12:08pm UTC](https://www.simscale.com/forum/t/project-support/94763/3 "2021-12-27T12:08:48Z")
Hi @ggiraldof Thank you for you help with this project to date. I have updated the flow domain and based the values used off a research paper i found. In terms of the ABL definition am i correct in saying it must be defined in 3D, We discussed the ABL definition in the past [here](https://www.simscale.com/forum/t/invalid-table-definitions/94639) Have i misunderstood the previous discussion? Thanks again Sam ---
**Author:** ![ggiraldof](https://www.simscale.com/forum/user_avatar/www.simscale.com/ggiraldof/32/30298_2.png) [@ggiraldof](https://www.simscale.com/forum/u/ggiraldof)\ **Post date:** [December 27, 2021, 1:51pm UTC](https://www.simscale.com/forum/t/project-support/94763/4 "2021-12-27T13:51:24Z")
Hi Sam, About the ABL, are you aware of this article? > **[Atmospheric Boundary Layer | How to Set up an ABL | SimScale](https://www.simscale.com/knowledge-base/atmospheric-boundary-layer-abl/)** > > In this article, you will learn how to set up an Atmospheric Boundary Layer (ABL) profile in CFD simulations. Join SimScale today! ---
**Author:** ![ss02150](https://www.simscale.com/forum/letter_avatar/ss02150/32/6_22734026db12803ebb3e059622ac3534.png) [@ss02150](https://www.simscale.com/forum/u/ss02150)\ **Post date:** [December 27, 2021, 7:02pm UTC](https://www.simscale.com/forum/t/project-support/94763/5 "2021-12-27T19:02:00Z")
Hi, Yes i have read this article previously, I believe when last going through this you had stated that i needed to define the X and Y coordinates in the table? Defining the X as constant at the location of the domain inlet,and defining Y at the lowest negative value, 0 and the upper positive value? ---
**Author:** ![ss02150](https://www.simscale.com/forum/letter_avatar/ss02150/32/6_22734026db12803ebb3e059622ac3534.png) [@ss02150](https://www.simscale.com/forum/u/ss02150)\ **Post date:** [December 28, 2021, 12:28pm UTC](https://www.simscale.com/forum/t/project-support/94763/6 "2021-12-28T12:28:04Z")
Edit: I have updated the velocity inlet and simply used a ABL with power law 0.17, does this now look correct? > **[SimScale Login](https://www.simscale.com/workbench/?pid=4228370608098992886&mi=spec%3A00d62e10-d1f8-4df6-ba79-0cd2fe56617d%2Cservice%3ASIMULATION%2Cstrategy%3A144&ps=analysis%2FboundaryConditions%2F5)** > > Log in to your SimScale account. SimScale makes high-fidelity engineering simulation technically and economically accessible. At any scale. In the cloud. ---
**Author:** ![ss02150](https://www.simscale.com/forum/letter_avatar/ss02150/32/6_22734026db12803ebb3e059622ac3534.png) [@ss02150](https://www.simscale.com/forum/u/ss02150)\ **Post date:** [January 3, 2022, 11:03am UTC](https://www.simscale.com/forum/t/project-support/94763/7 "2022-01-03T11:03:55Z")
Hi there @ggiraldof, I have made the amendments you suggested and re-meshed the model. Is the new ABL input acceptable as well as the new domain? (the domain was created based off a research paper so not identical to what you suggested) Further to this i checked the mesh in Mesh quality and noticed the non orthogonality was 76, which is too large when compared to the recommended values. ![image](https://www.simscale.com/forum/uploads/default/original/3X/c/4/c467ed3f16faff5e9abf3869c7b06e2b46d4c625.png) Is there a way to reduce this to a acceptable value? Link to project: [https://www.simscale.com/workbench/?pid=4228370608098992886&mi=spec%3A00d62e10-d1f8-4df6-ba79-0cd2fe56617d%2Cservice%3ASIMULATION%2Cstrategy%3A144&ps=analysis%2FboundaryConditions%2F5](https://www.simscale.com/workbench/?pid=4228370608098992886&mi=spec%3A00d62e10-d1f8-4df6-ba79-0cd2fe56617d%2Cservice%3ASIMULATION%2Cstrategy%3A144&ps=analysis%2FboundaryConditions%2F5) Regards, Sam ![image](https://www.simscale.com/forum/uploads/default/original/3X/f/c/fccfa190a6d3a84e811a13834e0027e0566f159d.png) ---
**Author:** ![ggiraldof](https://www.simscale.com/forum/user_avatar/www.simscale.com/ggiraldof/32/30298_2.png) [@ggiraldof](https://www.simscale.com/forum/u/ggiraldof)\ **Post date:** [January 12, 2022, 2:16pm UTC](https://www.simscale.com/forum/t/project-support/94763/8 "2022-01-12T14:16:37Z")
Hey back! Sorry for the late reply. Did you try running the simulation? I think this value for non-orthogonality should not prevent you from having good results.