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Phiper October 26, 2010 16:25

3d flow through fluid domain
Hey, this looks like the perfect forum for what I've been looking for so hopefully you guys can help.

I'm trying to model the flow of crude oil through a salt water domain vertically. As in it has a high initial velocity shooting straight up and then buoyancy will accelerate it until it comes to a terminal velocity. The flow would be turbulent since the high velocity and relatively low kinematic viscocity of crude oil (<30) would cause a low reynolds number.

I was wondering whether this flow should be considered incompressible (since I'm dealing with liquids) or compressible (since I'm dealing with deep depths) and/or nonviscous. The flow would have no boundaries so I figure it should be pretty simple, but I do not know what method of modeling with the navier-stokes equations I should use.

I want to write this code myself instead of using SolidWorks, which I think I have access to, because I need to be able to modify the oil as it flows (since it will slowly decompose), and I need data at the end that I can then pass to another model. I'm not familiar at all with SolidWorks however so if you think it can do that please tell me because that could save some time.

Thanks for any help!

otd October 26, 2010 18:10

[QUOTE=Phiper;280862]The flow would be turbulent since the high velocity and relatively low kinematic viscocity of crude oil (<30) would cause a low reynolds number.

Probably you mean high Reynolds number?

Can't help with your other questions. But anyone who can will want to know the depths you're dealing with, temperature vs depth for the salt water, initial velocity of the oil, etc.

Will you really have a contiguous column of oil? It appears that the oil released into the Gulf of Mexico recently (Deep Water Horizon?) broke up, some went to the bottom, some onto the surface, and some broke up into clouds of droplets at particular depths. How does your problem compare to that? If you're following decomposition, that suggests relatively long problem times.

Don't have answers, but suggest you might consider some of these questions before you start coding. This could be difficult.

Hope someone with more specific knowledge can help you.

Phiper October 26, 2010 18:55

Wow sorry. Yes a high Reynolds number.

This is the exact same idea as the BP deep horizon spill.. So this implies that the simulation would have up to a mile of depth, and decomposition would certainly occur. Thats why I was wondering what type of model I could use to be able to process the velocities of oil particles depending on their changing density and viscocity throughout the ascent. The initial volumetric flowrate would be something like 0.03680261457 m^3/s or 20000 bbls/day. Again, any help would be wonderful.

akhokhay October 28, 2010 08:28

I think u should use incompressible flow! speed of sound in water is around 1500m/s and roughly u need speed of 500m/s for oil, in order of compressible effects become important
Also feel free to consider it compressible it just waste some time that's all(I still need confirmation)
Maybe Reynolds stresses method is fine for turbulent modeling but I think it will take lots of time!

I suggest to use a commercial software unless u have that kind of time to code it!

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