331 lines
10 KiB
C++
Executable file
331 lines
10 KiB
C++
Executable file
/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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Module: FGMars.cpp
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Author: Jon Berndt
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Date started: 1/4/04
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Purpose: Models the Martian atmosphere very simply
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Called by: FGFDMExec
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------------- Copyright (C) 2004 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 Lesser 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 Lesser General Public License for more
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details.
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You should have received a copy of the GNU Lesser 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 Lesser 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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Models the Martian atmosphere.
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HISTORY
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--------------------------------------------------------------------------------
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1/04/2004 JSB Created
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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COMMENTS, REFERENCES, and NOTES
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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INCLUDES
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
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#include "FGMars.h"
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#include "FGState.h"
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namespace JSBSim {
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static const char *IdSrc = "$Id$";
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static const char *IdHdr = ID_MARS;
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/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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CLASS IMPLEMENTATION
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
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FGMars::FGMars(FGFDMExec* fdmex) : FGAtmosphere(fdmex)
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{
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Name = "FGMars";
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Reng = 53.5 * 44.01;
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/*
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lastIndex = 0;
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h = 0.0;
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psiw = 0.0;
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MagnitudedAccelDt = MagnitudeAccel = Magnitude = 0.0;
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// turbType = ttNone;
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turbType = ttStandard;
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// turbType = ttBerndt;
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TurbGain = 0.0;
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TurbRate = 1.0;
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*/
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bind();
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Debug(0);
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}
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//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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/*
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FGMars::~FGMars()
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{
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unbind();
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Debug(1);
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}
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*/
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//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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bool FGMars::InitModel(void)
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{
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FGModel::InitModel();
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Calculate(h);
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SLtemperature = intTemperature;
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SLpressure = intPressure;
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SLdensity = intDensity;
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SLsoundspeed = sqrt(SHRatio*Reng*intTemperature);
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rSLtemperature = 1.0/intTemperature;
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rSLpressure = 1.0/intPressure;
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rSLdensity = 1.0/intDensity;
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rSLsoundspeed = 1.0/SLsoundspeed;
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temperature = &intTemperature;
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pressure = &intPressure;
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density = &intDensity;
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useExternal=false;
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return true;
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}
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//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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bool FGMars::Run(void)
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{
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if (FGModel::Run()) return true;
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if (FDMExec->Holding()) return false;
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//do temp, pressure, and density first
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if (!useExternal) {
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h = Propagate->Geth();
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Calculate(h);
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}
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if (turbType != ttNone) {
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Turbulence();
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vWindNED += vTurbulence;
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}
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if (vWindNED(1) != 0.0) psiw = atan2( vWindNED(2), vWindNED(1) );
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if (psiw < 0) psiw += 2*M_PI;
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soundspeed = sqrt(SHRatio*Reng*(*temperature));
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Debug(2);
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return false;
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}
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//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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void FGMars::Calculate(double altitude)
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{
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//Calculate reftemp, refpress, and density
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// LIMIT the temperatures so they do not descend below absolute zero.
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if (altitude < 22960.0) {
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intTemperature = -25.68 - 0.000548*altitude; // Deg Fahrenheit
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} else {
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intTemperature = -10.34 - 0.001217*altitude; // Deg Fahrenheit
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}
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intPressure = 14.62*exp(-0.00003*altitude); // psf - 14.62 psf =~ 7 millibars
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intDensity = intPressure/(Reng*intTemperature); // slugs/ft^3 (needs deg R. as input
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//cout << "Atmosphere: h=" << altitude << " rho= " << intDensity << endl;
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}
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//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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// square a value, but preserve the original sign
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static inline double
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square_signed (double value)
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{
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if (value < 0)
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return value * value * -1;
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else
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return value * value;
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}
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void FGMars::Turbulence(void)
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{
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switch (turbType) {
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case ttStandard: {
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vDirectiondAccelDt(eX) = 1 - 2.0*(double(rand())/double(RAND_MAX));
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vDirectiondAccelDt(eY) = 1 - 2.0*(double(rand())/double(RAND_MAX));
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vDirectiondAccelDt(eZ) = 1 - 2.0*(double(rand())/double(RAND_MAX));
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MagnitudedAccelDt = 1 - 2.0*(double(rand())/double(RAND_MAX)) - Magnitude;
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// Scale the magnitude so that it moves
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// away from the peaks
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MagnitudedAccelDt = ((MagnitudedAccelDt - Magnitude) /
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(1 + fabs(Magnitude)));
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MagnitudeAccel += MagnitudedAccelDt*rate*TurbRate*State->Getdt();
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Magnitude += MagnitudeAccel*rate*State->Getdt();
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vDirectiondAccelDt.Normalize();
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// deemphasise non-vertical forces
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vDirectiondAccelDt(eX) = square_signed(vDirectiondAccelDt(eX));
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vDirectiondAccelDt(eY) = square_signed(vDirectiondAccelDt(eY));
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vDirectionAccel += vDirectiondAccelDt*rate*TurbRate*State->Getdt();
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vDirectionAccel.Normalize();
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vDirection += vDirectionAccel*rate*State->Getdt();
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vDirection.Normalize();
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// Diminish turbulence within three wingspans
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// of the ground
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vTurbulence = TurbGain * Magnitude * vDirection;
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double HOverBMAC = Auxiliary->GetHOverBMAC();
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if (HOverBMAC < 3.0)
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vTurbulence *= (HOverBMAC / 3.0) * (HOverBMAC / 3.0);
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vTurbulenceGrad = TurbGain*MagnitudeAccel * vDirection;
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vBodyTurbGrad = Propagate->GetTl2b()*vTurbulenceGrad;
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vTurbPQR(eP) = vBodyTurbGrad(eY)/Aircraft->GetWingSpan();
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// if (Aircraft->GetHTailArm() != 0.0)
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// vTurbPQR(eQ) = vBodyTurbGrad(eZ)/Aircraft->GetHTailArm();
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// else
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// vTurbPQR(eQ) = vBodyTurbGrad(eZ)/10.0;
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if (Aircraft->GetVTailArm())
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vTurbPQR(eR) = vBodyTurbGrad(eX)/Aircraft->GetVTailArm();
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else
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vTurbPQR(eR) = vBodyTurbGrad(eX)/10.0;
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// Clear the horizontal forces
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// actually felt by the plane, now
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// that we've used them to calculate
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// moments.
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vTurbulence(eX) = 0.0;
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vTurbulence(eY) = 0.0;
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break;
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}
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case ttBerndt: {
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vDirectiondAccelDt(eX) = 1 - 2.0*(double(rand())/double(RAND_MAX));
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vDirectiondAccelDt(eY) = 1 - 2.0*(double(rand())/double(RAND_MAX));
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vDirectiondAccelDt(eZ) = 1 - 2.0*(double(rand())/double(RAND_MAX));
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MagnitudedAccelDt = 1 - 2.0*(double(rand())/double(RAND_MAX)) - Magnitude;
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MagnitudeAccel += MagnitudedAccelDt*rate*State->Getdt();
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Magnitude += MagnitudeAccel*rate*State->Getdt();
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vDirectiondAccelDt.Normalize();
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vDirectionAccel += vDirectiondAccelDt*rate*State->Getdt();
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vDirectionAccel.Normalize();
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vDirection += vDirectionAccel*rate*State->Getdt();
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// Diminish z-vector within two wingspans
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// of the ground
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double HOverBMAC = Auxiliary->GetHOverBMAC();
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if (HOverBMAC < 2.0)
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vDirection(eZ) *= HOverBMAC / 2.0;
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vDirection.Normalize();
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vTurbulence = TurbGain*Magnitude * vDirection;
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vTurbulenceGrad = TurbGain*MagnitudeAccel * vDirection;
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vBodyTurbGrad = Propagate->GetTl2b()*vTurbulenceGrad;
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vTurbPQR(eP) = vBodyTurbGrad(eY)/Aircraft->GetWingSpan();
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if (Aircraft->GetHTailArm() != 0.0)
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vTurbPQR(eQ) = vBodyTurbGrad(eZ)/Aircraft->GetHTailArm();
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else
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vTurbPQR(eQ) = vBodyTurbGrad(eZ)/10.0;
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if (Aircraft->GetVTailArm())
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vTurbPQR(eR) = vBodyTurbGrad(eX)/Aircraft->GetVTailArm();
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else
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vTurbPQR(eR) = vBodyTurbGrad(eX)/10.0;
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break;
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}
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default:
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break;
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}
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}
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//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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// The bitmasked value choices are as follows:
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// unset: In this case (the default) JSBSim would only print
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// out the normally expected messages, essentially echoing
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// the config files as they are read. If the environment
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// variable is not set, debug_lvl is set to 1 internally
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// 0: This requests JSBSim not to output any messages
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// whatsoever.
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// 1: This value explicity requests the normal JSBSim
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// startup messages
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// 2: This value asks for a message to be printed out when
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// a class is instantiated
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// 4: When this value is set, a message is displayed when a
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// FGModel object executes its Run() method
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// 8: When this value is set, various runtime state variables
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// are printed out periodically
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// 16: When set various parameters are sanity checked and
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// a message is printed out when they go out of bounds
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void FGMars::Debug(int from)
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{
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if (debug_lvl <= 0) return;
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if (debug_lvl & 1) { // Standard console startup message output
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if (from == 0) { // Constructor
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}
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}
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if (debug_lvl & 2 ) { // Instantiation/Destruction notification
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if (from == 0) cout << "Instantiated: FGMars" << endl;
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if (from == 1) cout << "Destroyed: FGMars" << endl;
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}
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if (debug_lvl & 4 ) { // Run() method entry print for FGModel-derived objects
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}
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if (debug_lvl & 8 ) { // Runtime state variables
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}
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if (debug_lvl & 16) { // Sanity checking
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}
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if (debug_lvl & 32) { // Turbulence
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if (frame == 0 && from == 2) {
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cout << "vTurbulence(X), vTurbulence(Y), vTurbulence(Z), "
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<< "vTurbulenceGrad(X), vTurbulenceGrad(Y), vTurbulenceGrad(Z), "
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<< "vDirection(X), vDirection(Y), vDirection(Z), "
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<< "Magnitude, "
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<< "vTurbPQR(P), vTurbPQR(Q), vTurbPQR(R), " << endl;
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} else if (from == 2) {
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cout << vTurbulence << ", " << vTurbulenceGrad << ", " << vDirection << ", " << Magnitude << ", " << vTurbPQR << endl;
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}
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}
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if (debug_lvl & 64) {
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if (from == 0) { // Constructor
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cout << IdSrc << endl;
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cout << IdHdr << endl;
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}
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}
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}
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} // namespace JSBSim
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