DPM results same as in converged continuous flow

yoooodarulez · July 29, 2013, 04:58

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?

July 29, 2013, 04:58	Same results in DPM as in continuous phase	#1
yoooodarulez Member Nick Join Date: Nov 2009 Posts: 45 Rep Power: 16	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. Last edited by yoooodarulez; July 30, 2013 at 16:56.

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July 29, 2013, 06:29		#2
yoooodarulez Member Nick Join Date: Nov 2009 Posts: 45 Rep Power: 16	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)

July 30, 2013, 13:16		#3
yoooodarulez Member Nick Join Date: Nov 2009 Posts: 45 Rep Power: 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?