shells/applications/cylinderElastic/helpers/DetonationPressure.h

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// -*- C++ -*-
//
// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
//
//                                   Fehmi Cirak
//                        California Institute of Technology
//                           (C) 2004 All Rights Reserved
//
// <LicenseText>
//
// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
//
#ifndef DETONATIONPRESSURE_H
#define DETONATIONPRESSURE_H
#include <cmath>


namespace cylExp {
    struct DetonationPressure;
    struct PressurePulse;
}


struct DetonationPressure {
    
    double operator()(double time, double x, double y, double z) const 
        {
        // Beltman - Shepherd paper eq. A.7
        
        time += 0.0038;
        double timeShifted = time-0.00304575;
        
        double positionShifted = 1.5;   
        positionShifted += 0.76;
        
        const double p1 = 80.0e3;
        const double p2 = 2.6e6;
        const double p3 = 0.75e6;
        const double vcj = 2365.0;
        
        double tcj = (z+positionShifted)/vcj;
        double T = tcj/3.0;

        const double initialPressure = p1;
        
        if (timeShifted>tcj) {
            double pressure = (p2-p3)*std::exp((tcj-timeShifted)/T)+p3;
            return pressure-initialPressure;
        } else {
            return 0.0;
        }

    }   
};


struct PressurePulse {
    
    double operator()(double time, double x, double y, double z) const 
        {
            const double p2 = 2.6e6;
            const double vcj = 2365.0;
            
            double tcj = (z)/vcj;
            
            if (time>tcj) {
                return -p2;
            } else {
                return 0.0;
            }
    }   
};

#endif

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