120 lines
3.6 KiB
C++
120 lines
3.6 KiB
C++
/*******************************************************************************
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Module: FGAuxiliary.cpp
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Author: Jon Berndt
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Date started: 01/26/99
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Purpose: Calculates additional parameters needed by the visual system, etc.
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Called by: FGSimExec
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------------- Copyright (C) 1999 Jon S. Berndt (jsb@hal-pc.org) -------------
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This program is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free Software
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Foundation; either version 2 of the License, or (at your option) any later
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version.
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This program is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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details.
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You should have received a copy of the GNU General Public License along with
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this program; if not, write to the Free Software Foundation, Inc., 59 Temple
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Place - Suite 330, Boston, MA 02111-1307, USA.
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Further information about the GNU General Public License can also be found on
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the world wide web at http://www.gnu.org.
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FUNCTIONAL DESCRIPTION
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--------------------------------------------------------------------------------
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This class calculates various auxiliary parameters.
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REFERENCES
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Anderson, John D. "Introduction to Flight", 3rd Edition, McGraw-Hill, 1989
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pgs. 112-126
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HISTORY
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--------------------------------------------------------------------------------
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01/26/99 JSB Created
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********************************************************************************
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INCLUDES
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*******************************************************************************/
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#include "FGAuxiliary.h"
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#include "FGTranslation.h"
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#include "FGRotation.h"
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#include "FGAtmosphere.h"
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#include "FGState.h"
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#include "FGFDMExec.h"
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#include "FGFCS.h"
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#include "FGAircraft.h"
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#include "FGPosition.h"
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#include "FGOutput.h"
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#include "FGMatrix.h"
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static const char *IdSrc = "$Header$";
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static const char *IdHdr = ID_AUXILIARY;
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/*******************************************************************************
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************************************ CODE **************************************
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*******************************************************************************/
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FGAuxiliary::FGAuxiliary(FGFDMExec* fdmex) : FGModel(fdmex) {
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Name = "FGAuxiliary";
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vcas = veas = mach = qbar = pt = 0;
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psl = rhosl = 1;
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earthPosAngle = 0.0;
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}
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FGAuxiliary::~FGAuxiliary() {}
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bool FGAuxiliary::Run() {
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float A,B,D;
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if (!FGModel::Run()) {
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GetState();
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if(mach < 1) //calculate total pressure assuming isentropic flow
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pt=p*pow((1 + 0.2*mach*mach),3.5);
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else {
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// shock in front of pitot tube, we'll assume its normal and use
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// the Rayleigh Pitot Tube Formula, i.e. the ratio of total
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// pressure behind the shock to the static pressure in front
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B = 5.76*mach*mach/(5.6*mach*mach - 0.8);
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// The denominator above is zero for Mach ~ 0.38, for which
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// we'll never be here, so we're safe
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D = (2.8*mach*mach-0.4)*0.4167;
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pt = p*pow(B,3.5)*D;
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}
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A = pow(((pt-p)/psl+1),0.28571);
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vcas = sqrt(7*psl/rhosl*(A-1));
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veas = sqrt(2*qbar/rhosl);
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vPilotAccel = Translation->GetUVWdot() + Aircraft->GetXYZep() * Rotation->GetPQRdot();
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earthPosAngle += State->Getdt()*OMEGA_EARTH;
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} else {
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}
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return false;
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}
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void FGAuxiliary::GetState(void) {
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qbar = Translation->Getqbar();
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mach = Translation->GetMach();
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p = Atmosphere->GetPressure();
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rhosl = Atmosphere->GetDensitySL();
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psl = Atmosphere->GetPressureSL();
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}
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