turb1.hlp

MATLAB在飞行动力学和控制中应用的工具

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TURB1 is a Simulink subsystem which is contained in the Atmosphe-
ric Turbulence sublibrary of the library WINDLIB. It contains the
Dryden filters UDRYD1, VDRYD1, and WDRYD1 for longitudinal, late-
ral and vertical turbulence, respectively. The filters have been
implemented in masked subsystem blocks, in which the user must
specify the scale lengths Lug, Lvg, and Lwg, the standard devia-
tions sigma_ug, sigma_vg, and sigma_wg, and the velocity V (for
each of the three masked subsystem blocks!). The coefficients of
the Dryden filters are determined for the value of the airspeed V
which is specified in the dialog boxes from the blocks UDRYD1,
VDRYD1, and WDRYD1, i.e., V is assumed to be constant.

Only in those cases where the airspeed changes over a very large
range, it is recommended to use the subsystem TURB2, which takes
into account variations of the filter coefficients due to changes
in the true airspeed V. See TURB2.HLP for more info.

Outputvector from TURB1:
========================
  uwind = [uw vw ww uwdot vwdot wwdot]',

 (actually, this vector should be called ugust = [ug vg wg ...
 ... ugdot vgdot wgdot]', since the wind velocities and their
 time-derivatives from the subsystem TURB1 are equal to gust
 velocities only; contributions due to WIND(-shear) still have to
 be added to this vector!).

 uw   : wind (gust-) velocity along XB-axis of aircraft [m/s]
 vw   : wind (gust-) velocity along YB-axis of aircraft [m/s]
 ww   : wind (gust-) velocity along ZB-axis of aircraft [m/s]

 uwdot: time-derivative of uw [m/s^2]
 vwdot: time-derivative of vw [m/s^2]
 wwdot: time-derivative of ww [m/s^2]

TURB1 does not have any inputsignals.

Parameters which must be set in dialog boxes within TURB1:
==========================================================
Before starting a simulation of a system in which the subsystem
TURB1 is involved, the parameters of the masked subsystem blocks
UDRYD1, VDRYD1, and WDRYD1 have to be defined by double-clicking
these blocks and entering the correct values in their dialog-
boxes. These parameters are:

UDRYD1: Lug     = scale length for longitudinal turbulence [m]
        sigma_ug= standard deviation for longitudinal
                                                  turbulence [m/s]
        V       = value of airspeed, used to determine filter
                    coefficients for longitudinal turbulence [m/s]

VDRYD1: Lvg     = scale length for lateral turbulence [m]
        sigma_vg= standard deviation for lateral turbulence [m/s]
        V       = value of airspeed, used to determine filter
                         coefficients for lateral turbulence [m/s]

WDRYD1: Lwg     = scale length for vertical turbulence [m]
        sigma_wg= standard deviation for vertical turbulence [m/s]
        V       = value of airspeed, used to determine filter
                        coefficients for vertical turbulence [m/s]
More info:
==========
See UDRYD1.HLP, VDRYD1.HLP, and WDRYD1.HLP for more details about
the masked subsystem blocks from TURB1 (Dryden filters with con-
stant coefficients). More details about the Dryden filters with
coefficients that vary with V can be found in the helpfiles
TURB2.HLP, UDRYD2.HLP, VDRYD2.HLP, and WDRYD2.hlp.

See CWIND.HLP and BLWIND.HLP for more information on the imple-
mentation of constant wind and a wind-profile in the Earth's
boundary layer, respectively.

Type WINDLIB to open the Wind & Atmospheric Turbulence Library.

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The FDC toolbox, Copyright Marc Rauw 1994-1998.