# Thread: Flow equation help plz..

1. Hi, I'm a student in Civil engineering dept. and I've been searching for something to help out a senior student. Since we have no fluid background I've tried to search internet for it and its kinda difficult to figure it out.

What I'm trying to find is an equation that can solve something simple like this.

If I have a vertical wall and I paint on some liquid, like jelly or something, I need to predict the length which it sags.

Eg. If I paint 10 cm by 10 cm and thickness of say 2mm on a vertical wall, if I have the density/weight of the material can I predict how much it sags? like using gravity or something like that?

Sam

2.

3. You need viscosity for sure. It also depends how rigorous a solution you are going for. Also the materials you are describing are not likely Netwonian fluids, so you may need an emprirical approach where you consider them as Binghmam Plastic, or Power Law fluids, etc. From a first glance this is actually quite a complex problem. (The good news is someone will do a follow up post that points out a charmingly simple solution. Watch this space.)

4. the material I'll try will be epoxy so I guess its non-newtonian fluid as you've mentioned.

Ow... I hope there is a simple solution for this...

5. anyone have any idea for this problem? I still cant figure this out..

6. You may have to cough up \$31.50. If this article doesn't help some of its references might.

http://www.sciencedirect.com/science...2&searchtype=a

7. Hello Wiz,

The link seems to give me error

Could you please let me know the title of the journal?

Thank you
Sam

8. Science Direct:

A new method for the quantitative determination and prediction of sag and levelling in powder coatings
Original Research Article
Progress in Organic Coatings, In Press, Corrected Proof, Available online 2 March 2011,
Martin Bosma, Richard Brinkhuis, Enrico Rensen and Robert Watson View Abstract
http://www.sciencedirect.com/science...type=a#sec0015

9. Thank you again Wizard, I hope you have a great weekend!

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