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Effect Sloshing in a tank of water with CFX
Hello, i need help about my simulation
I am currently trying to simulate the splash effect on a water tank in the shape of a straight cylinder, with a density of 1000 kg / m3, not full. the objective is to determine the deformation of the surface as well as the forces generated on the walls of the tank to obtain the shear force generated at the base of the tank. when executing the program I get an error: Update failed for the Solution component in Fluid Flow (CFX). The solver failed with a non-zero exit code of: 2 I have uploaded the file to drive so that they can give it a revision if necessary: I do not detect the source of the error.:confused: I would be very grateful for your help. |
Based on what you have written, nobody can help, because there is nothing to be answered;
What settings did you choose? are there any external loads on the cylinder? How did you set the initial condition for water mass fraction? the only data you have provided is the density of water that is pathetic. .... You haven't provided anything So my answer can only be the following, It is definitely your fault that it doesn't work as this can be done in cfx. Rewrite it, add questions that will make your simulation work, and you will learn in the process. |
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Thank you for your answer.
i am very deacred with you, my configuration is not the correct one so i need to correct it, due to the error produced i do not achieve identify the root of the problem, simply can not converge, or that looks like. the volume is like: if (y <0.7 [m], 1,0) * if (y> 0.0 [m], 1,0) turbulence model: k-elipson total time 1s, 0.1s to step free surface tank diameter 7.92m, 4.57m height number of nodes: 288912 number of elements: 1476233 Initial velocity u: 1m / s v: 0 w: 0 relative pressure 1 atm |
There are no external charges on the tank.
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why is:
Initial velocity u: 1m / s this will cause a lot of slushing in the tank, so timestep of 0.1s is probably not apropriate What are you expecting from the simulation? if there are no loads, accelerations, or whatever on the tank the surface will be just flat. -Be sure to include gravitational acceleration. - the mesh where you predict the surface will be can be a bit finer maybe, as the surface will actually be smudged ower 3 elements unless some additional specific models for surface tension and surface compression will be included. if the simulation has problems converging in the start try smaller timestep or use adaptive timestep method. |
No isolated fluid regions were found. (this is normal?)
in the description of the error it also appears: ERROR # 001100279 has occurred in subroutine ErrAction. | *| Message: | *| Floating point exception: Overflow *ERROR # 001100279 has occurred in subroutine ErrAction. | *| Message: | *| Stopped in routine FPX: C_FPX_HANDLER | *| | *| An error has occurred in cfx5solve: | *| | *| The ANSYS CFX solver exited with return code 1. No results file | *| has been created. | *+ -------------------- Speed was a piece of advice I found on the web, I actually took it into account as a basis for testing the procedure. Basic settings: WATER AIR Morphology: Continuous fluid Reference pressure: 1 atm Buoyant Gravity x: 0 *************and: 9.81 m / s2 *************z: Acc Buoy.ref.Density 997 kg / m3 Acc = 3 [m / sec ^ 2] * sin (omg * t) omg = 9.98 [rad / sec] |
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How can I select double presicion?.
So far the other possible solutions have not been effective. aspect ratio 7.44 "The ANSYS CFX solver has terminated without writing a results file." thanks |
It is on the solver settings when you start the job in Solver Manager. You can also set it in CFX-Pre.
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could someone help me with a file that models the free surface of the water, in any mode?, because I suspect that the problem arises in the installation of the software and I would like to try it with some program that has been tested. For ANSYS 19.0 or lower
So far I still have the same error. "The ANSYS CFX solver has finished without writing to results file." |
I doubt that it is connected with program installation because if you are able to open CFXpre and solver than it works.
It must be the settings of the simulation, based on what you have written so far you are new to the cfd, and multiphase simulations aren't simple. That said it is not actually that hard to set up a problem like this. Is this the load on your tank (probably some kind of sinusoidal acceleration)? Acc = 3 [m / sec ^ 2] * sin (omg * t) omg = 9.98 [rad / sec] if yes, then why start with nonsense initial conditions. I would like to help but am not able to as I don't understand you, probably other people here on the forum cant also. Rewrite it, make it more for us to understand what you are actually doing etc.. |
Hello
Will I start from the basics, as would the expression for the volume of water in CFX for a square container ?. Created from the origin in the XY plane, coordinates (0,0) (0.3,0) (0,0.3) (0.3,0.3) and extruded in the Z direction of 0.25 m If you want the water level to be 0.2 m from the base |
I want to perform a simulation of a water tank with free surface, when running CFX I get the results of the attached image. Help me what these results mean, what could be the mistake
Thank youhttps://www.cfd-online.com/Forums/bl...3&d=1551167635 |
Effect Sloshing in a tank of water with CFX
I want to perform a simulation of a water tank with free surface, when running CFX I get the results of the attached image. Help me what these results mean, what could be the mistake
Thank you https://www.cfd-online.com/Forums/bl...3&d=1551167635 |
Check if you even have a free surface. you can make a surface where the water volume fraction is 0.5.
There you will see if the problem maybe lies in the reference density or some other settings. I would recommend that you crawl then walk then run. Make the simulation simple at first only get the water surface -> and then complicate with accelerations of your container. I would bet that you don't have a water surface here and that the water is "exploded" throughout the whole volume of the container And this thing always implies to all Numerical simulations īgarbage in garbage outī. I hope you know the boundary conditions of your simulation, based on previous posts you don't exactly. And if this is true how could We. Try to make posts we can answer more directly with lots of data and details. Imagine me asking You; my car is broken what is wrong? how is it possible for you to answer this question over the forum. But that is how I feel on this side of the forum; my simulation doesn't work what is wrong? Best I can do is to guess, but people here on the forum don't have time guessing other peoples problems. Again we would love to help but help us help you ;) |
Your simulation is numerically unstable and/or not converged. The numerical stability is covered in this related FAQ: https://www.cfd-online.com/Wiki/Ansy...do_about_it.3F
You should also consider a tighter convergence tolerance. |
Hello
I thought that the image could give you an idea of the reason of this error, I have prepared images that describe all the conditions for the simulation, please could you help me in finding the reason that generates the error mentioned abovehttps://www.cfd-online.com/Forums/bl...1&d=1551295722 https://www.cfd-online.com/Forums/bl...1&d=1551295741 https://www.cfd-online.com/Forums/bl...1&d=1551295756 Fluid buyoancy model: Density difference surface tension coefficient_ 0.072 N m^-1 Fluid specific initialization: Water (Volume fraction: VF ) Air (Volumen Fraction:1-Vf) Expressions: VF = if(y<1[m],1,0)*if(y>0.0[m],1,0) |
My post #17 says exactly what the problem is. But this is caused by many factors so you need to read the FAQ. I am not going to type them out again (that's why it is an FAQ).
You also have surface tension activated, and for a body of water this big it is highly unlikely surface tension is important. The surface tension model is also a very difficult model to use, requires extremely small time steps and makes numerical stability very difficult. Unless you need surface tension you should remove this model. |
I have modified: Timesteps = 0.0001
but the result does not come in any way to reality, I can not identify the reason Also I changed the geometry of the tank to one 10 times smaller https://www.cfd-online.com/Forums/bl...1&d=1551315517 |
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