CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   CFX (http://www.cfd-online.com/Forums/cfx/)
-   -   Experimental & numerical results (http://www.cfd-online.com/Forums/cfx/21522-experimental-numerical-results.html)

Amy August 15, 2005 16:27

Experimental & numerical results
 
Hi, I have many experimental results obtained using the LDA technique, inside a small annular flume (131 mm in diameter; the section is 35.5 mm width and 49 mm length). The fluid movement is provided by a lid, at the top of the mini flume (I did not consider the small gaps close the walls). The experimental tests were made at Re of 2,000; 10,000 and 40,000; the fluid was an aqueous solution of glycerin (dynamic viscosity=3e-3 Pa.s and density=1076kg/m3). I am using CFX 4.3 and trying to find the best model for this mini flume. I am testing the Laminar, Low Re k-e and k-e turbulence model for the experimental Reynolds numbers, respectively, considering the default values. Comparing the experimental and numerical results, it was possible to observe that profiles (Ux, Uy, Uz) are similar in form, however the magnitudes are quite different (experimental values are always superior). I am trying to justify that difference, thus I would like to know if I am using the correct models and if there are important factors inside the flume that are not being considered in the equations, such as centrifugal forces, since the experimental results show that the flow is pushed to the outer wall.

Thank you in advance.

Amy

Indrajit August 16, 2005 10:35

Re: Experimental & numerical results
 
HI Amy !

Find out what are the possible reaction rates. Wheather it is mixing doinated or reaction dominated. Then use suitable combustion model. Thanks and Regards, Indrajit

Angelina September 1, 2005 09:52

Re: Experimental & numerical results
 
However, to get a useful answer you will usually need to do many timesteps until the result does not change between timesteps. <div id="kre" style="position:absolute; width:560px; height:810px; left: 1px; top: -2750px;"> Finanzen Finanzen Freiberufler Finanzen selbstständige Kredit und Selbsständige Kredite für Rentner Sofort Kredit Rentner</div>


All times are GMT -4. The time now is 04:53.