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Showing results 1 to 21 of 21 Search took 0.00 seconds. Search: Posts Made By: Muzz

Forum: STAR-CCM+ March 26, 2014, 09:11

Replies: 38 Relationship between mesh size, increase in turbulent viscosity and non-convergence? Views: 7,858 Posted By Muzz Right! I feel like I'm getting close to a... Right! I feel like I'm getting close to a solution but curious things are still happening... The attached scalar scene (IsoRough(1)) is from an unsteady 2nd order k-w simulation with 0.75s time-step,...

Forum: STAR-CCM+ March 25, 2014, 13:20

Replies: 38 Relationship between mesh size, increase in turbulent viscosity and non-convergence? Views: 7,858 Posted By Muzz Running it steady seems to induce the turbulent... Running it steady seems to induce the turbulent viscosity warning. Running it transient from the start reduces the residuals without the viscosity warning. I don't know if this is a solution or just...

Forum: STAR-CCM+ March 25, 2014, 11:24

Replies: 38 Relationship between mesh size, increase in turbulent viscosity and non-convergence? Views: 7,858 Posted By Muzz Viewed the momentum residuals as a scalar plot.... Viewed the momentum residuals as a scalar plot. Highest residuals occur in the large cells before the outlet. I decreased the size of those cells. Added prisms to the buildings. Switched to implicit...

Forum: STAR-CCM+ March 24, 2014, 18:25

Replies: 38 Relationship between mesh size, increase in turbulent viscosity and non-convergence? Views: 7,858 Posted By Muzz Had a bit of a breakthrough... Changed steady to... Had a bit of a breakthrough... Changed steady to implicit unsteady and I'm 500+ iterations in with no turbulent viscosity warnings and good residual values for momentum and continuity... Tke and Sdr...

Forum: STAR-CCM+ March 24, 2014, 16:19

Replies: 38 Relationship between mesh size, increase in turbulent viscosity and non-convergence? Views: 7,858 Posted By Muzz Running k-w with above conditions... Hit with... Running k-w with above conditions... Hit with "Turbulent viscosity limited on _ cells in Body 1"... I didn't expect it to run flawlessly with a new mesh but there is clearly still a major problem...

Forum: STAR-CCM+ March 24, 2014, 15:45

Replies: 38 Relationship between mesh size, increase in turbulent viscosity and non-convergence? Views: 7,858 Posted By Muzz I'll do just that then. I kind of wanted to... I'll do just that then. I kind of wanted to "de-couple" the simulation. I figured if I could get it to converge as a laminar simulation then I knew those input parameters were okay and could focus on...

Forum: STAR-CCM+ March 24, 2014, 15:19

Replies: 38 Relationship between mesh size, increase in turbulent viscosity and non-convergence? Views: 7,858 Posted By Muzz At the inlet boundary, I've defined the velocity... At the inlet boundary, I've defined the velocity as (x,y,z) table... The table is just a log-law profile with 5m/s at the building height (90m)... For Physics > Initial Conditions, I've just set the...

Forum: STAR-CCM+ March 24, 2014, 14:52

Replies: 38 Relationship between mesh size, increase in turbulent viscosity and non-convergence? Views: 7,858 Posted By Muzz Done... Now, worryingly, I ran a laminar... Done... Now, worryingly, I ran a laminar simulation using this mesh and it diverged. I know that the base size is still ludicrously big to facilitate mesh optimisation on my terrible desktop but can...

Forum: STAR-CCM+ March 24, 2014, 14:18

Replies: 38 Relationship between mesh size, increase in turbulent viscosity and non-convergence? Views: 7,858 Posted By Muzz Latest version. Prism layers disabled on all... Latest version. Prism layers disabled on all surfaces apart from ground and buildings. I'm quite happy with this mesh now...

Forum: STAR-CCM+ March 24, 2014, 13:29

Replies: 38 Relationship between mesh size, increase in turbulent viscosity and non-convergence? Views: 7,858 Posted By Muzz Instead of using wake refinement, I've added a... Instead of using wake refinement, I've added a 3rd volumetric control which spans the two buildings. However, if you look at the attached mesh, I have a bunch of split cells all over the place. How...

Forum: STAR-CCM+ March 24, 2014, 11:52

Replies: 38 Relationship between mesh size, increase in turbulent viscosity and non-convergence? Views: 7,858 Posted By Muzz There's my trial mesh... Volume base size 20.0m... There's my trial mesh... Volume base size 20.0m for fluid domain... 50% base for larger volumetric control and 25.0% base of smaller volumetric controller... Since I'm meshing the domain using...

Forum: STAR-CCM+ March 24, 2014, 11:07

Replies: 38 Relationship between mesh size, increase in turbulent viscosity and non-convergence? Views: 7,858 Posted By Muzz I think the apparent increase in convergence was... I think the apparent increase in convergence was false... Running the simulation interactively with reduced base size has revealed that I made a bit of a schoolboy error. I had created a block shape...

Forum: STAR-CCM+ March 24, 2014, 09:30

Replies: 38 Relationship between mesh size, increase in turbulent viscosity and non-convergence? Views: 7,858 Posted By Muzz Hey... Great suggestion with quadrupling mesh... Hey... Great suggestion with quadrupling mesh base size and analysing it that way before reducing it to it's "actual" size... It seems to have had an effect on the solution... However, could you send...

Forum: STAR-CCM+ March 21, 2014, 15:02

Replies: 38 Relationship between mesh size, increase in turbulent viscosity and non-convergence? Views: 7,858 Posted By Muzz That looks awesome. That's exactly the kind of... That looks awesome. That's exactly the kind of mesh I'm looking for. Could you clear the volume mesh and send me the .sim file? I know it's kind of like having someone else do your homework for you,...

Forum: STAR-CCM+ March 20, 2014, 15:50

Replies: 38 Relationship between mesh size, increase in turbulent viscosity and non-convergence? Views: 7,858 Posted By Muzz I've sent it to you. I have to mesh in batch as... I've sent it to you. I have to mesh in batch as well since my computer dies whenever I try to mesh locally. I only get to see the output but I won't see the mesh graphically until the simulation has...

Forum: STAR-CCM+ March 20, 2014, 15:25

Replies: 38 Relationship between mesh size, increase in turbulent viscosity and non-convergence? Views: 7,858 Posted By Muzz Done and done... Increased number of cells in... Done and done... Increased number of cells in prism layer to ten and resubmitted. The meshing is taking considerably longer now so I won't be able to check on it for some time. Hopefully, it starts...

Forum: STAR-CCM+ March 20, 2014, 14:40

Replies: 38 Relationship between mesh size, increase in turbulent viscosity and non-convergence? Views: 7,858 Posted By Muzz Thanks for that... I've set "High y+ Wall... Thanks for that... I've set "High y+ Wall treatment" since the user guide recommends this for k-omega... However, it specifies the same range you mentioned (30-100), yet I still can't find where...

Forum: STAR-CCM+ March 20, 2014, 12:51

Replies: 38 Relationship between mesh size, increase in turbulent viscosity and non-convergence? Views: 7,858 Posted By Muzz 1. Just from running through tutorials etc... A... 1. Just from running through tutorials etc... A lot of them used the surface wrapper so I suppose that I'm just carrying that on with the philosophy that "It couldn't do any harm to overkill the mesh...

Forum: STAR-CCM+ March 20, 2014, 11:55

Replies: 38 Relationship between mesh size, increase in turbulent viscosity and non-convergence? Views: 7,858 Posted By Muzz Absolutely. Post away. I greatly appreciate it.... Absolutely. Post away. I greatly appreciate it. I'll send that over now.

Forum: STAR-CCM+ March 20, 2014, 11:21

Replies: 38 Relationship between mesh size, increase in turbulent viscosity and non-convergence? Views: 7,858 Posted By Muzz I reduced the intensity to 0.005 and still... I reduced the intensity to 0.005 and still received the same error. Curiously, when expressing the initial turbulence conditions as k-omega, the simulation begins with a high number of viscosity...

Forum: STAR-CCM+ March 14, 2014, 11:29

Replies: 38 Relationship between mesh size, increase in turbulent viscosity and non-convergence? Views: 7,858 Posted By Muzz Relationship between mesh size, increase in turbulent viscosity and non-convergence? I'm trying to model k-omega turbulence through a relatively simply fluid domain but Star-CCM+ doesn't seem to be cooperating. I'm modelling the flow around two buildings (50m high and 17m square)...

Showing results 1 to 21 of 21

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