Lecture 05 Notes - EGN 3353C Fluid Mechanics Static...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
EGN 3353C Fluid Mechanics Lou Cattafesta MAE Dept. University of Florida 3 ± Static equilibrium of above element leads to N 21 specific weight s PPP gz γ ρ Δ =−= Δ (*) P Δ∝ (and is usually negligible in gases for small changes in depth) If point 1 is taken at the “free surface” open to the atmosphere then 2 atm PP P g h == + o Leads to definition of gage pressure gage Pg h = (amount pressure is above local atmospheric pressure) o Similar concepts for absolute and vacuum pressures From (*), 0 lim z Pd P g zd z Δ→ Δ Δ ( sign comes from z direction positive upward so that dP <0 when dz >0) General Vector Form: p g ∇= G G or ˆˆ Pi j k P g k xy z ⎛⎞ ∂∂ + + = ⎜⎟ ⎝⎠ G . Can you see that this reduces to
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
EGN 3353C Fluid Mechanics Lou Cattafesta MAE Dept. University of Florida 4 () 0 only 0 P PP x x z P y y =→ ≠ = Pd P g zd z ρ == We can integrate 2 21 1 P P P gdz Δ= − = if we know ( ) z and ( ) gz If const and gc o n s t ( ) 12 Pg z z g z Δ =− = Δ ± Reasonable for small depth changes For stratified fluids w/ const g , ( ) N 2 2 2 1 HO SG z d z Δ= Example : 321 ρρ >> Why?
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 08/17/2011 for the course EGN 3353C taught by Professor Lear during the Spring '07 term at University of Florida.

Page1 / 7

Lecture 05 Notes - EGN 3353C Fluid Mechanics Static...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online