ENGR 100- Midterm Exam Guide - Comprehensive Notes for the exam ( 17 pages long!)
Document Summary
Power density: power flow (p) through a surface (of area a). Power density = p/a = u3. U is fluid velocity (m/s), is fluid density (kg/m3) In a fictitious flux tube, cross section a (m2) and length (m); tube walls parallel to streamlines. Power, p (w), flows into surface thru area a: general fluid flow set-up. Fluid flow still laminar, but not uniform: streamlines bend. Still in a fictitious flux tube: tube walls parallel to streamlines, which are still parallel to each other: conservation of mass. If steady state, no buildup of matter in flux tube. 1 a1 u1 = 2 a2 u2 ie. the mass flow rate au is constant anywhere in the flux tube (this is the continuity equation generally for gases) Suppose we found a nice site with a constant wind speed of ui. Let"s put up a wind turbine with area at to extract power from this wind.
