1.2 - 1.4 Flashcards
In the standard atmosphere, the temperature range is considered to be _____.
Linear
Pg. 11
The negative of the temperature gradient is commonly referred to as the _____.
Lapse rate
Pg. 11
What is the definition of “geometric altitude?”
The altitude measured from mean sea level and measured in units of length.
Wikipedia
What is the definition of “geopotential altitude?”
The geopotential altitude is the geometric altitude corrected for variations in gravity.
Wikipedia
What does the Reynolds number describe?
A measure of the relative magnitude of the pressure forces in relation to the viscous shear forces.
Pg. 14
Outside the boundary layer, shear forces are _____.
Negligible.
Pg. 14
The pressure gradient across the boundary layer is _____, due to _____.
- Insignificant
- The very thin nature of the boundary layer.
Pg. 14
For high Reynolds number flows, the viscous shear forces are _____ compared to ______ forces.
Small
Pressure
Pg. 15
True or False
For flow at high Reynolds numbers, the pressure forces acting on a body can be closely approximated from an inviscid flow analysis, outside the boundary layer.
True
Pg. 15
True or False
For 2D flow over streamlined bodies, at high RE and low AOA, pressure forces contribute significantly to drag.
False, pressure forces do not contribute a significant amount of drag under these conditions.
Pg. 15
When do pressure forces dominate the drag?
When boundary layer seperation occurs.
Pg. 15
Boundary layer separation is commonly referred to as a _____.
Stall
Pg. 15
Pressure forces acting on an aircraft at high RE can be closely estimated from what type of analysis?
Inviscid analysis (outside the boundary layer).
Pg. 15
The curl of the velocity vector is typically called the _____.
Vorticity
Pg. 16
True or False
Vorticity cannot be generated in an inviscid flow.
True
Pg. 16
