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-   -   DPM results same as in converged continuous flow (https://www.cfd-online.com/Forums/fluent/121446-dpm-results-same-converged-continuous-flow.html)

yoooodarulez July 29, 2013 04:58

Same results in DPM as in continuous phase
 
Dear all,

I am having problems calculating the lift and drag coefficients of a s809 wing in a 2phase flowfield (air+rain droplets).I am running the continuous phase first and get both a 1st and a 2nd order convergence.Then i insert the dpm parameters in define>models>dpm and set the wing boundary condition but it seems like im getting the same results as in continuous phase.Any suggestions?Thanks in advance.

yoooodarulez July 29, 2013 06:29

My input for DPM is:

-Interaction with continuous phase
-10 continuous phase iterations per DPM iteration
-Unsteady Particle tracking
-Particle Time Step size 0.001
-Number of Time Steps 1
-Max number of Steps 500
-Step Length factor 5
-Spherical drag law
-Droplet breakup/TAB/y0/2 parcels

and for the injections i use a surface type injection released from a plane ahead of my wing in the YZ plane which is releasing inert particles of water liquid with properties namely:

-x vel:the mainstream velocity 29.215
-y vel:the velocity computed from Gunn kinzner equation -3.77327
-diameter:0.0009
-start time 0
-stop time 1000
-total flow rate 0.87645 kg/s (but in here i havent included any area value i have just computed this mumber by multiplying LWC with the mainstream x-velocity)

yoooodarulez July 30, 2013 13:16

Ok let me pose another question since i figured it out what was wrong anyways.Is there any way to increase the splashed particles apart from introducing more particles?I kept increasing the surfaces from 1 (initially) to 4 surfaces releasing particles and the particles released did increase but the splashed particles came to a limit as it seems.Any suggestions?


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