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Aero input and outputs: Difference between revisions
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→Stall hysteresis, normalized:
Tags: Mobile edit Mobile web edit |
Tags: Mobile edit Mobile web edit |
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| Line 115: | Line 115: | ||
What I have understood at this point: | What I have understood at this point: | ||
By setting, say | By setting, say | ||
<hysteresis_limits unit="DEG"> | <hysteresis_limits unit="DEG"> | ||
<min>5.0</min> | <min>5.0</min> | ||
<max>17</max> | <max>17</max> | ||
</hysteresis_limits> | </hysteresis_limits> | ||
17 deg is typically the stall angle for a wing. | 17 deg is typically the stall angle for a wing. | ||
stall-hyst-norm, normally at 0 ('good condition'), switches to 1 ('bad condition') at 17 deg | stall-hyst-norm, normally at 0 ('good condition'), switches to 1 ('bad condition') at 17 deg alpha-deg (or corresponding alpha-rad value, different from alpha-wing-rad if wing incidence is not zero). | ||
Later on, it returns back to 0 only when alpha-deg comes down to 5 deg (that is with some 'delay'). Close to the usual hysteresis behavior (usually, iron magnetization vs magnetic field, with magnetic field h corresponding to alpha angle for us), but the delay is not dependent on the max value attained by the variable alpha. A kind of 'rectangular' hysteresis loop, more simple but already good for aerodynamics (linear or turbulent) regimes. | Later on, it returns back to 0 only when alpha-deg comes down to 5 deg (that is with some 'delay'). Close to the usual hysteresis behavior (usually, iron magnetization vs magnetic field, with magnetic field h corresponding to alpha angle for us), but the 'delay' (the return alpha value) is always 5 deg, not dependent on the max value attained by the variable alpha. A kind of 'rectangular' hysteresis loop, more simple but already good for aerodynamics (linear or turbulent) regimes. | ||
This stall-hyst-norm (0 or 1 values) can then be used as a parameter for tables, to set some command sensitivity, lift coefficient, moment, etc, to hold longer in it's 'bad' condition even when the cause has ceased. Stall holds for a longer time, like turbulent regime in the real case. | This stall-hyst-norm (0 or 1 values) can then be used as a parameter for tables, to set some command sensitivity, lift coefficient, moment, etc, to hold longer in it's 'bad' condition even when the cause has ceased. Stall holds for a longer time, like turbulent regime in the real case. | ||