# khalidb77@gmail.com

 Register Blogs Members List Search Today's Posts Mark Forums Read

 June 17, 2007, 01:46 khalidb77@gmail.com #1 Luis Guest   Posts: n/a Hi I have a pipe flow I was consider the pipe as 2 D geometry I chose turbulence intensity and hydraulic diameter for turbulent specification method. I need now to estimate the value of hydraulic diameter in order I predict the value of turbulence intensity from it? Can anybody tell me how can I estimate it ? Thanks in advance Luis

 June 17, 2007, 02:13 About Estimating Hydrulic diameter #2 khalidb77@gmail.com Guest   Posts: n/a Also which of the turbulence specification methods being most accurate for pipe flow? Thanks

 June 17, 2007, 08:09 Re: About Estimating Hydrulic diameter #3 Phil Guest   Posts: n/a Hydraulic diameter is the diameter of the inlet. If you don't have a circular inlet you should estimate what the diameter would be if it were circular. Turbulence intensity can be calculated from the diameter and Reynolds number. You should look up boundary conditions in the user guides for these equations and descriptions. I always use intensity and hydraulic diameter but remember the turbulence intensity will change as soon as the fluid enters the model. So it may not matter! Phil

 June 17, 2007, 11:03 Re: About Estimating Hydrulic diameter #4 LK Guest   Posts: n/a thanks phil to the reply. My geometry actually is circular Which it a pipe but I draw it as 2 D ? so should i estimate new diameter for the inlet or I took the original diameter to the pipe? Thanks

 June 18, 2007, 01:34 Re: About Estimating Hydrulic diameter #5 Wani Guest   Posts: n/a If your geometry is circular, I recommend you to use axisymmetry simulation.

 June 18, 2007, 01:44 Re: About Estimating Hydrulic diameter #6 LK Guest   Posts: n/a I cannot use axisymetric because i have water flow in the button of the pipe and air in top? What did you think there is ability to use axisymetric in problem like this? REGARDS LK

 June 18, 2007, 12:33 Re: About Estimating Hydrulic diameter #7 Fayyaz Hussain Guest   Posts: n/a as a student of FLUENT i think axisymmetric is best but if you cant use axisymmetric due to geometric restrictions then it is better to do simulation in 3 D.

 June 18, 2007, 15:33 Re: About Estimating Hydrulic diameter #8 Phil Guest   Posts: n/a If you have water in the bottom and air in the top it's a multiphase problem and you should be using a special model like the volume of fluid model. I don't know of any reason why any dimensional configuration cannot be used with this sort of problem. Phil

 June 19, 2007, 01:17 Re: About Estimating Hydrulic diameter #9 LK Guest   Posts: n/a Phil I was already use VOF model but i need to know was axisymetric in my problem allowed or no? furthermore I am not mean there is no dimensional configuration cannot be use in my problem ? If you remember my first question is how much the value of hydrulic diameter should i enter into the inlet I mean how can I predict it? Thanks LK

 Thread Tools 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 On Pingbacks are On Refbacks are On Forum Rules

All times are GMT -4. The time now is 09:17.