文档介绍：Project Assignment #1
Aerodynamic Analysis of the BWB Wind Tunnel Model
Sample Solution
Prof. David L. Darmofal
Department of Aeronautics and Astronautics
Massachusetts Institute of Technology
September 29, 2005
1 Data
Table 1 contains geometric data for the full-scale BWB. Table 2 contains data for the wind tunnel.
For now, assume that the air is at standard sea level conditions (. the temperature, density,
pressure, and viscosity) in the wind tunnel test section.
Symbol Parameter Value
2
Sref Reference Area (trapezoidal wing) 7,840 ft
2
Swet Wetted Area 31,324 ft
b Wing span 280 ft
cmac Mean aerodynamic chord ft
Table 1: Geometric data for full-scale BWB
Symbol Parameter Value
Model scale 1/47
U freestream velocity 50 and 100 mph
3
freestream density sl/ft
2
freestream kinemativ viscosity -04 ft /s
a freestream speed of sound ft/s
2
q freestream dynamic pressure lb/ft
Table 2: Wind tunnel data
2 Aerodynamic Model
To estimate the aerodynamic forces and moment on the BWB in the tunnel, a vortex lattice
calculation bined with a semi-empirical estimate of the skin friction and pressure drag (CDf
and CDp, respectively). The vortex lattice calculation provides estimates for the lift coefficient
(CL), the induced drag coefficient (CDi), and the pitching moment coeffic