Fluids

Fluids

mass flow rate problem

    • salsabeel
      Subscriber
      hello ,please can any one help me my problem is that after end simulation and check the mass flow rate at inlet and outlet there is a large difference from the experiment data .for example my target mass flow is15 kg/s but the report result show 116 kg/s nI work on vof multiphase open channel model,velocity at inlet and pressure outlet BC at outlet ,2D transient and s k-e turbulent modelnthanksn
    • Keyur Kanade
      Ansys Employee
      Few things to check - nPlease check mesh. Does it have sufficient refinement? What is quality? Min orthogonal quality should be above 0.1. nIs your case converged? Have you created any report definition? Can you upload residuals image? nPlease cross check extends of your domain in Fluent using Domain - Mesh - Scale. Make sure you have using correct scale. nPlease make sure you have sufficient small time step. It should converge in each time step. nPlease check if you can use PISO scheme. nRegards,nKeyurnHow to access Ansys Online Help DocumentnHow to show full resolution imagenGuidelines on the Student CommunitynHow to use Google to search within Ansys Student Communityn
    • salsabeel
      Subscriber
      thank you for your reply .ntime step =0.01 ,down are images for residual and mesh quality,my case do not converged because of reversed flow but solution being steady when i monitor velocity i observed there is stability in solution after giving more time .ncan you tell me more what you mean Have you created any report definition? pleasennnn
    • YasserSelima
      Subscriber
      From the left menu, select report definition - new ... and define the critical variable that you want to monitor. You can monitor the change of this variable with time, from monitors.n
    • salsabeel
      Subscriber
      ,in which version available this option i,m used ansysR16.1 there no report definition choicenn
    • YasserSelima
      Subscriber
      It is where you are. If you want to monitor force, right click force and select new ... flux .. surface or volume integral.nThis is changed in later versions.n
    • salsabeel
      Subscriber
      ok,thank you for helpingn
    • YasserSelima
      Subscriber
      You are welcome!n
    • salsabeel
      Subscriber
      hello, ,when i monitor value of velocity magintud by contour it's less than velocity magintud by vector is that ok .or both must be equal?nand i have question about velocity magintud and x _velocity what diffrence between them in domain if simulation 2d .nn
    • YasserSelima
      Subscriber
      nThis is not a monitor. The monitor would be a plot of a certain velocity, or averaged velocity at some area with respect to the timenThe difference between the contours and the vectors in the scale .. do you have a difference in the values?nx_velocity is the x component of the velocity. the velocity has x component and y component ... each could be +ve or -ve or zero. Velocity_magnitude = sqrt(x_velocity^2 + y_velocity^2) and is always +venn
    • salsabeel
      Subscriber
      thank you for your reply,yes i meant extract the contour not monitor the accuracy of solution nhow is the difference in scale and it for same body or geometry ?as you see in images above there is a difference
    • YasserSelima
      Subscriber
      uncheck the Auto range box .. then enter the maximum and minimum values to get the scale you wantn
    • salsabeel
      Subscriber
      thanks for your kinds to answer on my simple questions, how i or based on what to inter max and min value to get scale? and which one more accurate to show the results contour graphics or vector graphics .n i have cases with different geometry but constant physical properties and i want make a mesh study for my project ,should i do it for every case or one case enough ?nis there a way to know velocity of water value only at inlet and outlet ,contour and vector graphs given mixture velocity only.nbest regards n
    • YasserSelima
      Subscriber
      based on what you have .. like try 0 and 0.4 and see if this covers your range or not. Having max and minimum is for comparison between cases. So do it for all cases with the same values to compare. nIf you are using VOF, no velocity available for each phase. to have velocity difference, use the mixture modeln
Viewing 13 reply threads
  • You must be logged in to reply to this topic.