I am running a conjugate heat transfer problem in ANSYS Fluent with an i5 CPU & 8 GB RAM. The entire simulation takes about 3-4 days. The concern is that ANSYS Fluent is not fully utilizing the CPU (only 25 % utilization) & RAM (only about 4 GB - 50 % utilization). Is there any way to make ANSYS Fluent to utilize the CPU & RAM as much as possible so that I can get the simulation done within a day or two?
The amount of RAM the system will utilize mostly affected by the number of mesh elements, the element type, and the type of solver the simulation employed. So no need to be worry why the simulation does not use total available RAM. It means that your system is capable of doing the simulation with finer mesh if needed.
Regarding the low CPU utilization, you better to check your system's power plan as well, the power management settings including Min/Max Processor state and system cooling policy. Sometimes the system avoids high percentage for the cooling purpose regardless of above setting as well which differs from one system to another.
Computation pace depends on the no.of equations and also no. of cells which for obvious reason prohibits running 3D simulations on desktop computer. You can run it in parallel mode depending on how many processors you have. Also you can run FLUENT in background mode using the journal file. This would reduce RAM load by getting rid of GUI and also would enhance the computation pace.
@ Abdelkader - I don't have any GPU. Is it possible to run parallel in normal CPUs?
i5 system has 4 cores. So since you are only using single core the system is only 25% loaded. You have to use parallel processing in order to used all the CPU's
@Somenath Chatterjee - I have checked it - The ANSYS Fluent is set to use all 4 cores.
If all the 4 cores are committed and yet the system is using only 25% power collective..and 50% ram only indicate that full memory is not required to process the calculations. May be you can make the mesh more dense and then check if the CPU usage is higher or not. If it is higher for denser mesh means the computer is using the amount of processing power it needs to process the calculation at speed.
Probably you are using only one core for simulation. Specify all 4 cores. If your memory consumed (see task manager) is > 8Gb then much of the time is wasted in swapping data and waiting. My experience says that mesh should be
I think you might need to set the priority of Ansys fluent to High or more in the task manager, so that when your are using it you will be able to get more of your computer recourses.
Regards
Saheed
the first choice is parallel processing.
then you should be thriky in using methods and algotithms
forceclosing explorer and other application may free ram and hasten your work.
I have the same problem. I use Parallel ANSYS Fluent. the RAM is got stucked in 4GB while the system I use has 16GB. the speed of simulation is too low and with other system, which are weaker than mine, time of simulation is less. I can't find what is wrong. is there any way to commit a specified RAM to a program?
any help or idea is appreciated.
The amount of RAM the system will utilize mostly affected by the number of mesh elements, the element type, and the type of solver the simulation employed. So no need to be worry why the simulation does not use total available RAM. It means that your system is capable of doing the simulation with finer mesh if needed.
Regarding the low CPU utilization, you better to check your system's power plan as well, the power management settings including Min/Max Processor state and system cooling policy. Sometimes the system avoids high percentage for the cooling purpose regardless of above setting as well which differs from one system to another.
@ Mahdi - Thanks for your answer - Its really very informative and helpful to me
I also have the same issue.
My CPU usage is 100% but memory only 36%. My system have 64GB Ram, Intel Xeon CPU E5-2620v3 @ 2.40GHz 2.40GHz...
During analysis, I am using parallel processing 6core...
From above discussion, my understanding is that I can not utilize the whole RAM on the current simulation and the usage of RAM depend on the complexity of computational problem.
Hi guys please help I am using ansys workbench thermal-electric connect to the single university licence with other users but I keep getting general error occurred on the solver I am not sure if the problem is licence related or it is my computer which has 2GB RAM but it sometimes works.
Niaz Bahadur Khan,
Probaly....your case is not large enough to take advantage of the huge RAM. Your bottleneck here is the CPU.
e.g.: two phase case with 20kk cells does not need 64gb ram.
@NIaz and @ Hakeem please ensure that you are using 64bit operating system on a 64 bit hardware. It sometime happens because of the 32 bit operating system you use on 64 bit machine because of which your software use only half of the power your machine is capable of.
According to the information from "sharcnet" (link below). It is possible to configure Ansys in a such way, when it will fill RAM cash before writing result files to the HDD in a sequence mode which is faster than writing files one by one.
https://www.sharcnet.ca/Software/Ansys/17.0/en-us/help/ans_bas/Hlp_G_BAS19_4.html
But for me it didn't work , solver in static mechanical recognize config information, but memory allocation do not change during the solving process..
You can try information from that link, may be this will help you.
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