曝光臺(tái) 注意防騙
網(wǎng)曝天貓店富美金盛家居專營(yíng)店坑蒙拐騙欺詐消費(fèi)者
the vortex breakdown point over the wing surface at high angles of attack.
Effects of s/des//p. The sideslip has a strong influence on the vortex break-
down phenomenon. Assume that, for a certain delta wing held at some angle of
attack, the vortex breakdown occurs at the trailing edge as shown in Fig. 8.lla.
If this wing is in sidcslip on the windward side, the vortex breakdown point pro-
gresses towards the wing apex, whereas on the lee side it moves aft and away
from the trailing edge as shown in Fig. 8.llb. In other words, the vortex on the
windward side becomes unstable and that on the lee side becomes more stable.
It should be noted that, by vortex stability, we mean the fluid dynamic stability
of the vortex motion and not the aircraft stability. In essence, the effective sweep
of the windward side decreases and that of the lee side increases as illustrated in
Fig. 8.12. This asymmetric vortex burst also generates an asymmetric flow field
STABILITY AND CONTROL PROBLEMS AT HIGH ANGLES OF ATTACK 683
a),B : 0 b) p > 0 c) pincreasing
Fig. 8.11 Effect ofsideslip on vortex breakdown.
"
┏━┳━┓
┃ ┃ ┃
┣━╋━┫
┃ ┃ ┃
┗━┻━┛
a) Zero sideslip, Aetir.R = Aetit:L = A
Aett,
= A-p
b) With sideslip
Fig. 8.12 Concept of effective sweep for delta wings in sideslip.
.,
684 PERFORMANCE, STABIL17Y, DYNAMICS, AND CONTROL
┏━━━━┳━━━━━━━━━━━━┳━━━━━━━━┳━━━┓
┃ ┃ ┃NNlt \ ┃ ┃
┃ ┃--_J .x ~~ - uWco. ┃ ┃ ┃
┃ ┣━━━┳━━━━━━━━┻━━━━━━━━┫ ┃
┃ ┃ ┃ ┃ ┃
┣━━━━╋━━━╋━━━━━━━━┳━━━━━━━━╋━━━┫
┃ ┃ ┃ ┃ ┃ ┃
┣━━━━╋━━━┻━┳━━━━━━╋━━━━━━━━╋━━━┫
┃ ┃ J_ ~:┃x-lc, ┃7 N ┃\ ┃
┃ ┃s ┃ ┃~,7.B ┃ ┃
┃ISTASLE ┃-1 ┃ ┃ ┃ ┃
┃-1N ┃ ┃ ┃ ┃ ┃
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