UDF for splashed mass in impinging sprays
 

Hi Community,

I am modeling an impinging spray. I have added a UDF for the splashed mass (see attachment). However, the simulation crashes every time when the spray impacts the surface.

Now I have two questions:
1) Did I do something wrong in the spray_mass.c?
2) Or do I need to define film_splash.c too?

It is the first time, I am using a UDF, and I am inexperienced with that. So I would be happy about any hint you could give me. Thank you!

Christoph

Hello Christoph,

You have altered the IN macro list to include passed_splash_var as a VALUE variable (not advised). splash_var (splash energy/weber no.) is not included within the list of CONVERGE variables being passed to the splash_mass.c UDF and hence is not available. Your log file should state an error resolving "passed_splash_var" as an argument. It is only available within splash_crit.c and splash_radius.c. Users are advised to not include passed_* variables from one UDF to different UDFs. Different UDFs have different variables being passed onto them.

We'd be happy to develop a working UDF for you to offer what you seek. Please contact support@convergecfd.com . Please use your official email for all correspondence with Convergent Science. Please mention the your UDF request, attach a case setup (if possible) and add my name, and the cfd-online thread, as reference.


Sincerely,

Hello Christoph,

To add to my previous comment, and since you pointed it out yourself, you can achieve what you're looking for by relying on film_splash.c, instead of splash_mass.c. Within film_splash.c, uncomment the film splash model routine (user_film_splash_*) you require and modify the splashed mass (rmsplash) calculation.

Hope this helps.

Sincerely,