# Preesure changes in fliud movement

1. Jul 16, 2009

### superb

Hope you guys can help me in solving this problem...

There one grooved surface seal the another smooth surface from bottom ...
inside the grooved surface there will be a liquid.... this grooved surface will rotate at certain speed , while the smooth surface on the bottom will remain stationary.

The problem is the pressure changes result from the movement of the fluid inside the grooves will lift the grooved surface.... how to calculate this pressure different and lifting force ?

p/s what i know, the high speed fluid will result the low pressure... how come there lifting force?

2. Jul 16, 2009

### Danger

Welcome to PF, Superb.
I'm having a bit of trouble understanding your question. Do you mean that you have a stationary seal with oiled grooves in the interior surface within which the shaft rotates?

3. Jul 16, 2009

### superb

yes, thats what i mean

could you help me.... can i use the Bernoulli equation for this application?

4. Jul 16, 2009

### Danger

I'm afraid that I can't help you, pal. I never finished high-school. My first thought is that it would be a surface-tension effect of the lubricant. You really have to wait for a real scientist to answer you, though.

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