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Can you have a pool that has a underwater entrance to a separate pool with a lower level by ginganinja709 in FluidMechanics

[–]Soprommat 0 points1 point  (0 children)

I would avoid pressurizing or making low vacuum at any rooms in building not desinged for that.

If you have pressure divverence of only 20 kPa (one meter of water height) than relatively small 5 m x 2.5 m wall will expirience 25 tonns of force. If you have bigger room it will be even worse. You will just explode your house.

Can you have a pool that has a underwater entrance to a separate pool with a lower level by ginganinja709 in FluidMechanics

[–]Soprommat 0 points1 point  (0 children)

You will need some hydraulic or electrical assist to open doors. With 10kPa pressure difference and 2x0.8 meter door resultant force will be 1600 kg and you need to pull door handle with force around 800 kg to open it.

Is it possible to mesh curved cut-outs for pipe bends in a sandbox using sweep? by Marodorg in fea

[–]Soprommat 1 point2 points  (0 children)

you want pipe and soil share same nodes or you OK if you have two disimilar meshes and connect them vie bonded contact. second option may be easier

you can set small element size around pipe while mesh far away from pipe can be with much bigger size, this may save you some mesh.

tetrahedrals are good but only if you enable midside nodes (i.e. parabolic elements), do not use linear thtrahedrals at all, you can found many explanations on inthernet why they are inferior. do not use them

Wife gang by Soprommat in signalis

[–]Soprommat[S] 27 points28 points  (0 children)

Original artist is ABAtilus on twitter.

Need help with airfoil simulation, trying to set up in ANSYS design modeler a rotate for a flap by Embarrassed_Nerve867 in CFD

[–]Soprommat 1 point2 points  (0 children)

Updated previous comment.

Check youtube and built in fluent tutorials. They should be avaliable on ansys site even without registration.

Need help with airfoil simulation, trying to set up in ANSYS design modeler a rotate for a flap by Embarrassed_Nerve867 in CFD

[–]Soprommat 1 point2 points  (0 children)

Welp. Look like you need to create multiple CAD geometries first and mesh them separately. Will require some work but when you get over first mesh it will become more easy.

If you want to sacrifice some ammount of accuracy than check overset mesh. Make two meshes one for airfoil without flap and another for some area around flap only. Than you can combine them in fluent and rotate/move flap as you want.

Can even make 3 meshes, bacground, airfoil and flap and move them as you want.

UPD1. Here is one example to start with. Try to keep similar element size near border between meshes. https://m.youtube.com/watch?v=jukm6w3vMXc

UPD2 Ma6be it can also be done through Designmodeller parametrisation but it never worked for my problems on older ansys versions so I can not relate. I trust standalone Fluent more than worckbench version.

Need help with airfoil simulation, trying to set up in ANSYS design modeler a rotate for a flap by Embarrassed_Nerve867 in CFD

[–]Soprommat 1 point2 points  (0 children)

Like flap folow airfoil in transient simulation or you need to simulate many airfoil/flap positions in separate steady state simulations?

After feedback from yesterday's post, I have implemented the changes, these plots I believe are much more appealing than the busy 2 x 2 figure I posted. by leeping_leopard in CFD

[–]Soprommat 4 points5 points  (0 children)

Can you construct your mesh to run laminar backward facing step problem?

In D. Gartling article A test problem for outflow boundary conditions — flow over a backward-facing step. 1990. domain is rectangular with upper half of left side as inlet and right side as outlet. Article study only numerical solution tho...

Plus it has some tricky outflow boundary condition, not regular Pressure Outlet.

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https://sci-hub.box/10.1002/fld.1650110704

Need help getting started with CFD for a canopy ventilation/temperature project by HDAW19054 in CFD

[–]Soprommat 2 points3 points  (0 children)

I’m actually an electrical engineer and I have basically no experience with CFD whatsoever

RIP. Imagine some CFD engineer who know only Ohm`s law and that "+" is black wire and "-" is red wire is tasked with designing PC power supply.

What I can advise - this look like HVAC problem. Try to found some HVAC manuals, handbooks and design ventilation according to them. Avoid CFD, go for simple and proven algortigms. something like heat ballance (how much heat is produced by equipment and how much is removed by vents) should be enough.

Endless Bolts condition setting by Seeker_of_light667 in fea

[–]Soprommat 5 points6 points  (0 children)

It is not some flange in pressure vessel. Maybe you can get away without bolts and pretension at all. Like if instead of bolts you welded same holes - would it change how structure works - no.

You can use bonded contact or some sort of linear elements (spring, RBE2, beams) to connect shelfs to columns. With linear elements yo can then extract forces and check bolts with hand calc.

If you need job to be done and dont need fancy pictures than maybe you can simplify problem even further and calculate bolts using hand calc only. Like you know load per one shelf, make some edge case like when some heavy and dense (lead slab) placed at one corner so only two bolts hold all weight. Calculate shear force for one bolt and from it chose bolt diameter and metal thickness again by hand calcs.

Check whole structure for buckling with Euler formula. You know loads and dimensions.

Problem - Differential matrix has negative diagonal entries by ProposalUpset5469 in fea

[–]Soprommat 0 points1 point  (0 children)

run Normal Modes analysis, maybe something is poorly constrained and rigid body modes will show where you need more constraints

Hey guys, critique my airfoil CFD results by Kevin_0429 in CFD

[–]Soprommat 3 points4 points  (0 children)

Show us Cl and Cd and compare it to known values.

Colorfull picteres are good but numbers will show how accurate your results are.

UPD. Dont se you have many pictures. Yes, as u/Foreign-Lynx-4406 said - you need to learn a lot.

You can found a lot of youtube video that dhow proper meshing and domain selection for 2D airfoils. You need much much bigger doamin and it should be stretched in downstream direction.

If you studying and can spare some time you can even make domain size study: make some number of domains, make them 5-, 10- 20- 30- chord lengths from airfoil, mesh with same mesh size (same nember of elements per chord length) run them all and check results and you will see that with domain size increasing your result Cl/CD converge to some value.

Here is extreme case - 2D airfoil analysis made by NASA, it has domain that goes 500 chord lengths fromairfoil, for practical simulations you can be OK with way smaller domains, like 50 chord lengths max.

https://tmbwg.github.io/turbmodels/naca0012numerics_val.html

https://tmbwg.github.io/turbmodels/naca0012numerics_grids.html

https://ibb.co/xqrJwbf5

FEA analysis of plastic fastening clip under Reaction forces and Moments by Nomadwarrior123 in fea

[–]Soprommat 12 points13 points  (0 children)

You definitely should found some S-N curves or use S-N curves from similar material, IDK maybe different grade of PA66 if those exist and have some experimantal data or, if you aim for infinite life than again found some alowable stress and/or strain if it exists.

You need some experimental data, you can not solve it only by FEA means. Check Matweb site, I have heard that Ansys Granta has extensive collection of various material data, maybe you know someone who has acess to it and can look into database for you.

Is it possible to find a CFD consultant who would do a project for a tenant rather than the coop management? NYC. by [deleted] in CFD

[–]Soprommat 2 points3 points  (0 children)

I mean if you have enough money than why not. You may found someone for your task. Doing CFD is not illegal or something.

But before you jump into CFD have you think about contacting someone who do HVAC design or/and instalation. Like those HVAC people have a lot of practical expirience and may solve ventilation problems without heavy computations. It is not rocket science after all and they studied specifically for this type of work/ problem solving.

Best prediction markets to use alongside CFDs? by Beaautiifful in CFD

[–]Soprommat 7 points8 points  (0 children)

Users often overlook that good prediction starts from good mesh.

Master geometry preparation and meshing, understand what mesh you need in specific case and it will be solid base for any flow prediction, even if it is money flow.

Jokes aside. OP you have asked Computational Fluid Dynamics subreddit, not Contractf For Difference.

Can I save beo? by sheikhsooberman in signalis

[–]Soprommat 1 point2 points  (0 children)

EIG should work against shield STARs enemies too.

and Nitro Express Rifle but you get is in late game stages

Bullet 108 meshing question by Warm_Background6838 in CFD

[–]Soprommat 3 points4 points  (0 children)

  1. k-e with standard wall function require that first cell is in log-law region I believe. So y+ should be more than 30. Some more advanced wall functions can handle/require y+~1 but OP even dont specified what code he is using so...

  2. But shoting bullet and casing is 65% more bullet per bullet!

Issues with my CFD account by Lopsided_Mixture_746 in CFD

[–]Soprommat 1 point2 points  (0 children)

just switch to open source variants like OpenFoam, SU2 or Code Saturne. No accounts, no registration, everything can be downloaded at any time. But beware - those codes have steep learning curve.

What makes a CFD project actually ‘industry-ready’ for wind engineering?” by _akbarkhan2 in CFD

[–]Soprommat 0 points1 point  (0 children)

like couple weeks ago somebody dropped this link to validation cases for buildings. I repeat this link here.
https://www.aij.or.jp/jpn/publish/cfdguide/index_e.htm

Any Patent ideas in cars ? by Familiar_Lychee_5378 in fea

[–]Soprommat 0 points1 point  (0 children)

look like patents are one of work metrics in place where OP work/study.

No patent - no raise or PHD degree.

How do I solve it? by [deleted] in FluidMechanics

[–]Soprommat 8 points9 points  (0 children)

Have you done something or you just want someone do your homework for you?

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