(adsbygoogle = window.adsbygoogle || []).push({}); Fluid Mechanics: Flow Between Parallel Plates--Force Balance Equation

1. The problem statement, all variables and given/known data

http://antishift.org/image.php?id=16807&size=full [Broken]

2. Relevant equations

I know the equation for shear, tau=viscosity*velocity gradient. and pressure is obviously force/area.

3. The attempt at a solution

I solved this problem using navier-stokes equations, and using the assumptions given in the problem. however, the homework graders wrote to use force-balance equations instead, as stated in the problem. ><;;

The professor went over a similar example of a cylindrical fluid element, where the area factor was simply pi*r^2. however, i'm confused by the plates being infinite, so i can't seem to figure what the area is. how do i calculate the area of the fluid element? is it simply dy*dx? how is the pressure/pressure gradient affect being that the plates are infinite? I just need to know what the force balance equation looks like.

Here's a picture of my professor's lecture slide about the cylindrical fluid element and its force balance equation: http://antishift.org/image.php?id=16802&size=medium" [Broken]

Thanks!

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Fluid Mechanics: Flow Between Parallel Plates-Force Balance Equation

Can you offer guidance or do you also need help?

Draft saved
Draft deleted

**Physics Forums | Science Articles, Homework Help, Discussion**