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// Include Section
#include <iostream>
#include <cstdlib>
#include <cmath>
#include <string>
#include <iomanip>
using namespace std;
// This funtion computes the burnout altitude and the
// coast altitude of a model rocket.
// The first 6 parameter are the input data
// to the function. Parameter 7 and 8 return the results
void computeA (double massR, // Rocket Mass (g)
double massE, // Engine Mass (g)
double massP, // Propellant Mass (g)
double dia, // Diameter of Rocket (mm)
double advTh, // Avg thrust of Engine (N)
double burnD, // Burn Duration (s)
double& altB, // Burnout Altitude (m)
double& altC); // Coast Altitude (m)
const double density = 1.2; // kg/m^3
const double cd = .75; // drag coefficient of stndrd rocket
const double gravity = 9.8; // gravity on earty
const double pi = 3.14; // constant variable for PI
double avg_mass; // average mass during boost phase of rocket
double k; // half atmospher density*drag coeff*area
double vb; // burnout velocity
double area; // area of the rocket
double avgTh; // Thrust of engine in Newtons
double coastmass;
// Main Program
int main()
{
// constants
// Variable Declarations
double massR; // the mass of the rocket in grams
double massE; // the mass of the engine in grams
double massP; // mass of the propelland in grams
double avgTh; // Thrust of engine in Newtons
double burnD; // burn duration of the engine
double dia; // diameter of rocket in mmt
char good; // loop input answer
double altB;
double altC;
// Output Identification
system("CLS");
cout << "In Class #7 - "
<< "Rocket Burnout Velocity\n\n";
// This funtion computes the burnout altitude and the
// coast altitude of a model rocket.
// The first 6 parameter are the input data
// to the function. Parameter 7 and 8 return the results
do {
//
// Get rocket sample data
//
cout << "Enter the mass of the rocket (grams) => ";
cin >> massR;
cout << "Enter the mass of the engine (grams) => ";
cin >> massE;
cout << "Enter the mass of the propellant (grams) => ";
cin >> massP;
cout << "Enter the diameter of the rocket (in millimeters) => ";
cin >> dia;
cout << "Enter the average thrust of the engine (Newtons) => ";
cin >> avgTh;
cout << "Enter the burn duration of the engine (seconds) => ";
cin >> burnD;
// Calculation conversions
computeA(massR, massE, massP, dia, avgTh, burnD, altB, altC);
cout << fixed << setprecision(1) << endl;
cout << endl;
cout << "The burnout altitude is " << altB << " meters/second." << endl;
cout << "The coast altitude is " << altC << " meters/second." << endl;
cout << "Would you like to run the program again (Y or N)? ";
cin >> good;
cout << endl;
cout << endl;
} while (good == 'y');
cout << "\n\nEnd Program.\n";
return 0;
}
void computeA(double massR, // Rocket Mass (g)
double massE, // Engine Mass (g)
double massP, // Propellant Mass (g)
double dia, // Diameter of Rocket (mm)
double advTh, // Avg thrust of Engine (N)
double burnD, // Burn Duration (s)
double& altB, // Burnout Altitude (m)
double& altC) // Coast Altitude (m)
{
massR = massR / 1000;
massE = massE / 1000;
massP = massP / 1000;
dia = dia / 1000;
dia = (dia / 2);
avg_mass = massR + massE - (massP * .5);
coastmass = massR + massE - massP;
area = pi * (dia*dia);
k = ((.5 * 1.2) * .75 * area);
vb = sqrt((avgTh - (avg_mass*gravity)) / k) * tanh((burnD / avg_mass)
* sqrt(k * (avgTh - avg_mass*gravity)));
altB = (avg_mass / k) * log(cosh((burnD / avg_mass)*sqrt(k*(avgTh - avg_mass*area))));
altC = (coastmass / (2 * k))*log(((k*(vb*vb)) / (coastmass*area)) + 1);
}
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Mar 23, 2016 at 8:24pm