added mass

February 20, 2007, 17:11

Hi! Has anybody been concerned by the problem of added mass in the presence of free surface? We are starting to investigate this phenomenon on the models in the laboratory and we want to compare our results with CFD calculations. What kind of UDF sholud be written?

Regards

Kuba Broniszewski

February 23, 2007, 09:52

Dear Kuba,

can you explain the physics of the problem better.

Are you refering to "virtual mass" which is a term that shows up when one looks at the force on a submerged body moving through a fluid?

regards,

Bak_Flow

February 23, 2007, 10:39

Bak yes it is indeed the same. Virtual mass is important in two instnaces 1. While trying to dampen the instantaneos fluctaution in turbulence..Tchens theory, 2. In bubbly flows. Fluent cannot handle VM properly in momentum eqautions. Leads to divergence for gas liquid flows. but I have made it possible to work wiht it. Is tricky. If yo encounter difficualites mail me at kp@dal.ca

February 20, 2007, 17:11	added mass	#1
Kuba Broniszewski Guest Posts: n/a	Hi! Has anybody been concerned by the problem of added mass in the presence of free surface? We are starting to investigate this phenomenon on the models in the laboratory and we want to compare our results with CFD calculations. What kind of UDF sholud be written? Regards Kuba Broniszewski

February 23, 2007, 09:52	Re: added mass	#2
Bak_Flow Guest Posts: n/a	Dear Kuba, can you explain the physics of the problem better. Are you refering to "virtual mass" which is a term that shows up when one looks at the force on a submerged body moving through a fluid? regards, Bak_Flow

February 23, 2007, 10:39	Re: added mass	#3
kp Guest Posts: n/a	Bak yes it is indeed the same. Virtual mass is important in two instnaces 1. While trying to dampen the instantaneos fluctaution in turbulence..Tchens theory, 2. In bubbly flows. Fluent cannot handle VM properly in momentum eqautions. Leads to divergence for gas liquid flows. but I have made it possible to work wiht it. Is tricky. If yo encounter difficualites mail me at kp@dal.ca

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