# Droplet initial location

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 March 16, 2004, 02:31 Droplet initial location #1 Sang-Jin Lee Guest   Posts: n/a Hi, there, There is an example about droplet simulation in STAR-CD tutorial Ch.2. When we use STAR subroutine, DROICO, to place the initial location of droplet, (xd,yd,zd) will be used for it. By the way, in case of that there are two or more initial locations of droplet, how can we make it? Would you please give me an advice? Thanks in advance!

 March 17, 2004, 03:28 Re: Droplet initial location #2 Richard Guest   Posts: n/a Each time DROICO is called, it can only inject one droplet, whose position, type, velocity etc are specified by XY, YD, ZD, IDRT, UD, VD, WD etc. STAR will keep calling DROICO for this iteration or time-step until DROICO chooses not to inject another droplet. Specifically, until IDRT is returned unchanged from its input value.

 March 18, 2004, 22:10 Re: Droplet initial location #3 Sang-Jin Lee Guest   Posts: n/a Thank you very much, Richard. As result, you mean it's impossible to make 2 or more droplet initial position by using STAR-CD? I heard it can be with local coordinate system, but I'm not familiar with it. Perhaps do U have an idea about it?

 March 19, 2004, 03:46 Re: Droplet initial location #4 Richard Guest   Posts: n/a You can definitely inject more than 1 droplet with DROICO. My last posting was my best attempt to explain how to do it. Maybe if you look at the example coding which is commented out in the header of the subroutine? I seem to remember this shows how to inject 10 droplets.

 March 19, 2004, 10:46 Re: Droplet initial location #5 Michiel Guest   Posts: n/a Hi there, I think this will solve your problem. EQUIVALENCE( UDAT05(001), IDR ) now you can program a initial location depending on the idr number. for example n=mod(idr,max_init_locations) if (n.eq.0) n=max_init_locations if (n.le.10) then xd= yd= zd= elseif(n.le.20) then xd= yd= zd= elseif xd= yd= zd= endif good luck

 March 19, 2004, 19:18 Re: Droplet initial location #6 Sang-Jin Lee Guest   Posts: n/a Thank you very much, Richard and MIchiel. I had misunderstood what you explained to me at first, Richard. I'm sorry about it and thank you again. Now I can make more than 2 holes. Michiel, your kind explain was so great. Thank your really so much.