SimScale CAE Forum

Help needed to solve a species concentration distribution in fish market


Hello Team,

TMA is the species which is emitted in a closed fish market assuming from above image. so assuming TMA is the species emitted from a closed fish market. I encountered a crazy idea, to simulate the distribution of TMA with respect to the flow field in the closed fish market. basically i dont have any experimental data or past simulations similar to the following link.

in the above link, the editor explained the source generation rate or calculation of volumetric source generation rate for the entire car park based on number of cars.

in a similar way, i assume x number of similar fish present in a closed fish market which will be emitting TMA per each fish. if this is the case , can any one please suggest a good article to calculate the ppm in a closed fish market to track the TMA ppm concentration.

if the above approach is not possible, i am thinking to solve atleast in this way

here is the project link

in this case the editor simply added the diffusion coefficient and showed the distribution of species into atmosphere. i am thinking to simulate in this way if the first way is not possible. now i came up with a challenge. wherever i have a group of fish on the table is available, i am thinking to define this surface as a source generation, however i have to define the velocity on that fish group surface. practically this is not a physical velocity surface. so is there any other way to assign the surface with species emission (at a group of fish) with out velocity addition on the surface.

maybe a bit complex or ambiguous. looking forward to hear from the peers. thanks for your time and consideration.



I’d personally lean towards using volumetric passive scalar sources, as per the first project that you linked. Although I’d not select the whole domain as a source, I’d try to keep the source(s) close to the fish.

But either approach that you take, you would first need to, somehow, have an idea of how much TMA is emitted per fish. Something along the lines of “TMA emissions for 1 fish account for 0.02 mL/s”. Finding this information would be the hardest part, IMO.


Hello Ricardopg,

i am really thankful for your response. yes i completely agree with your point to find out the TMA emissions per fish. i am keen to know

how you got this value. please let me know how you got this value. thankyou.




Oh that was just a random number to exemplify what sort of information would be needed to determine ppm levels. Finding the real emission in articles/internet is your task at hand.