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Use the density values from the environment subsystem, to properly handle

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density variations due to humidity.
This commit is contained in:
andy 2002-06-10 08:47:29 +00:00
parent f12ba10c47
commit 0cabedaa4f
8 changed files with 30 additions and 21 deletions
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12
src/FDM/YASim/Airplane.cpp
View file

@ -667,7 +667,8 @@ void Airplane::runCruise()
{
setupState(_cruiseAoA, _cruiseSpeed, &_cruiseState);
_model.setState(&_cruiseState);
_model.setAir(_cruiseP, _cruiseT);
_model.setAir(_cruiseP, _cruiseT,
Atmosphere::calcStdDensity(_cruiseP, _cruiseT));
// The control configuration
_controls.reset();
@ -691,7 +692,8 @@ void Airplane::runCruise()
for(i=0; i<_thrusters.size(); i++) {
Thruster* t = ((ThrustRec*)_thrusters.get(i))->thruster;
t->setWind(wind);
t->setAir(_cruiseP, _cruiseT);
t->setAir(_cruiseP, _cruiseT,
Atmosphere::calcStdDensity(_cruiseP, _cruiseT));
}
stabilizeThrust();
@ -708,7 +710,8 @@ void Airplane::runApproach()
{
setupState(_approachAoA, _approachSpeed, &_approachState);
_model.setState(&_approachState);
_model.setAir(_approachP, _approachT);
_model.setAir(_approachP, _approachT,
Atmosphere::calcStdDensity(_approachP, _approachT));
// The control configuration
_controls.reset();
@ -732,7 +735,8 @@ void Airplane::runApproach()
for(i=0; i<_thrusters.size(); i++) {
Thruster* t = ((ThrustRec*)_thrusters.get(i))->thruster;
t->setWind(wind);
t->setAir(_approachP, _approachT);
t->setAir(_approachP, _approachT,
Atmosphere::calcStdDensity(_approachP, _approachT));
}
stabilizeThrust();

7
src/FDM/YASim/Atmosphere.cpp
View file

@ -53,10 +53,11 @@ float Atmosphere::getStdDensity(float alt)
return getRecord(alt, 3);
}
float Atmosphere::calcVEAS(float spd, float pressure, float temp)
float Atmosphere::calcVEAS(float spd,
float pressure, float temp, float density)
{
static float rho0 = getStdDensity(0);
float densityRatio = calcDensity(pressure, temp) / rho0;
float densityRatio = density / rho0;
return spd * Math::sqrt(densityRatio);
}
@ -91,7 +92,7 @@ float Atmosphere::calcVCAS(float spd, float pressure, float temp)
return Math::sqrt((7*p0/rho0)*(tmp-1));
}
float Atmosphere::calcDensity(float pressure, float temp)
float Atmosphere::calcStdDensity(float pressure, float temp)
{
return pressure / (R * temp);
}

4
src/FDM/YASim/Atmosphere.hpp
View file

@ -10,9 +10,9 @@ public:
static float getStdDensity(float alt);
static float calcVCAS(float spd, float pressure, float temp);
static float calcVEAS(float spd, float pressure, float temp);
static float calcVEAS(float spd, float pressure, float temp, float density);
static float calcMach(float spd, float temp);
static float calcDensity(float pressure, float temp);
static float calcStdDensity(float pressure, float temp);
// Given ambient ("0") pressure/density/temperature values,
// calculate the properties of static air (air accelerated to the

6
src/FDM/YASim/Model.cpp
View file

@ -84,7 +84,7 @@ void Model::initIteration()
localWind(pos, _s, v);
t->setWind(v);
t->setAir(_pressure, _temp);
t->setAir(_pressure, _temp, _rho);
t->integrate(_integrator.getInterval());
t->getTorque(v);
@ -191,11 +191,11 @@ void Model::setGroundPlane(double* planeNormal, double fromOrigin)
_ground[3] = fromOrigin;
}
void Model::setAir(float pressure, float temp)
void Model::setAir(float pressure, float temp, float density)
{
_pressure = pressure;
_temp = temp;
_rho = Atmosphere::calcDensity(pressure, temp);
_rho = density;
}
void Model::setWind(float* wind)

2
src/FDM/YASim/Model.hpp
View file

@ -50,7 +50,7 @@ public:
void setGroundPlane(double* planeNormal, double fromOrigin);
void setGroundEffect(float* pos, float span, float mul);
void setWind(float* wind);
void setAir(float pressure, float temp);
void setAir(float pressure, float temp, float density);
// BodyEnvironment callbacks
virtual void calcForces(State* s);

4
src/FDM/YASim/Thruster.cpp
View file

@ -61,11 +61,11 @@ void Thruster::setWind(float* wind)
for(i=0; i<3; i++) _wind[i] = wind[i];
}
void Thruster::setAir(float pressure, float temp)
void Thruster::setAir(float pressure, float temp, float density)
{
_pressure = pressure;
_temp = temp;
_rho = _pressure / (287.1f * _temp);
_rho = density;
}
}; // namespace yasim

2
src/FDM/YASim/Thruster.hpp
View file

@ -42,7 +42,7 @@ public:
// Runtime instructions
void setWind(float* wind);
void setAir(float pressure, float temp);
void setAir(float pressure, float temp, float density);
virtual void init() {}
virtual void integrate(float dt)=0;
virtual void stabilize()=0;

14
src/FDM/YASim/YASim.cxx
View file

@ -28,6 +28,7 @@ static const float CM2GALS = 264.172037284; // gallons/cubic meter
static const float KG2LBS = 2.20462262185;
static const float W2HP = 1.3416e-3;
static const float INHG2PA = 3386.389;
static const float SLUG2KG = 14.59390;
void YASim::printDEBUG()
{
@ -236,8 +237,10 @@ void YASim::copyToYASim(bool copyState)
double ground = getACModel()->get3DModel()->getFGLocation()->get_cur_elev_m();
// cout << "YASIM: ground = " << ground << endl;
float pressure = fgGetDouble("/environment/pressure-inhg") * INHG2PA;
float temp = fgGetDouble("/environment/temperature-degc") + 273.15;
float pressure = fgGetFloat("/environment/pressure-inhg") * INHG2PA;
float temp = fgGetFloat("/environment/temperature-degc") + 273.15;
float dens = fgGetFloat("/environment/density-slugft3")
* SLUG2KG * M2FT*M2FT*M2FT;
// Convert and set:
Model* model = _fdm->getAirplane()->getModel();
@ -274,7 +277,7 @@ void YASim::copyToYASim(bool copyState)
model->setGroundPlane(gplane, rad);
// air
model->setAir(pressure, temp);
model->setAir(pressure, temp, dens);
}
// All the settables:
@ -366,10 +369,11 @@ void YASim::copyFromYASim()
_set_Velocities_Wind_Body(v[0]*M2FT, -v[1]*M2FT, -v[2]*M2FT);
_set_V_rel_wind(Math::mag3(v)*M2FT); // units?
float P = fgGetDouble("/environment/pressure-inhg") * INHG2PA;
float T = fgGetDouble("/environment/temperature-degC") + 273.15;
_set_V_equiv_kts(Atmosphere::calcVEAS(v[0], P, T)*MPS2KTS);
float D = fgGetFloat("/environment/density-slugft3")
*SLUG2KG * M2FT*M2FT*M2FT;
_set_V_equiv_kts(Atmosphere::calcVEAS(v[0], P, T, D)*MPS2KTS);
_set_V_calibrated_kts(Atmosphere::calcVCAS(v[0], P, T)*MPS2KTS);
_set_Mach_number(Atmosphere::calcMach(v[0], T));