# Problems with residuals??

 User Name Remember Me Password
 Register Blogs Members List Search Today's Posts Mark Forums Read

 LinkBack Thread Tools Search this Thread Display Modes
 November 29, 2000, 04:48 Problems with residuals?? #1 Peter Kolb Guest   Posts: n/a Hi CFD-users, I'm a FLUENT 5.4.- user and I try to simulate the flow inside a stirred tank. For the motion of the stirrer I use the MRF-Model. The viscous model is the standard k-epsilon. I begin my calculations with very low rotational speed and after reaching a destined convergence, I increase the speed. When I postulate small scale residuals it's no problem for the x-velocity, y-velocity, z-velocity, k and epsilon to get a small value. At 10^-7 they all reach a kind of "steady state" where no changes could be recognized; but the continuity reach a stedy state at 10^-6. When I now increase the rotational speed step by step, all residulas will find "this steady state" at the value 10^-7 again except for the continuity. The residual for the continuity is increasing while I increase the speed. To my questions: 1)Is this normal that the residual for the continuity is increasing while I increase the speed? 2)What adjustments do I have to change to solve this problem? Solve Control Solution: Under-relaxation factors Pressure 0.3 Momentum 0.7 Turbulence Kinetic Energy 0.8 Turbulence Dissipation Rate 0.8 Viscosity 1.0 Density 1.0 Body Forces 1.0 Discretization Pressure PRESTO! Momentum First Order Upwind Pressure-Velocity Coupling SIMPLE Turbulence Kinetic Energy First Order Upwind Turbulence Dissipation Rate First Order Upwind Thanks Peter

 Thread Tools Search this Thread Search this Thread: Advanced Search Display Modes Linear Mode

 Posting Rules You may not post new threads You may not post replies You may not post attachments You may not edit your posts BB code is On Smilies are On [IMG] code is On HTML code is OffTrackbacks are Off Pingbacks are On Refbacks are On Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post tommymoose ANSYS Meshing & Geometry 6 December 1, 2020 12:12 spacecraft STAR-CCM+ 2 September 13, 2010 09:57 Tan FLUENT 3 February 10, 2009 11:05 Martin CFX 2 January 2, 2007 23:10 HS FLUENT 1 November 7, 2005 06:45

All times are GMT -4. The time now is 22:20.

 Contact Us - CFD Online - Privacy Statement - Top