/******************************************************************
 * FUNCTION: volume - working space volume variations and         *
 *                    derivatives                                 *
 * FILENAME volume.c                                              *
 * PROGRAMMER I.Urieli    (FORTRAN)                               *
 *        E. Malroy   (C Translation)                             *
 * DATE:      11/30/94  (FORTRAN), 03/12/96 (C Translation)       *
 * LAST MODIFIED: by I.Urieli 01/16/97                            *
 * INCLUDE:  <math.h>,"adiabatic.h","define.h"                    *
 * GLOBAL VARIABLES: myeng                                        *
 * PROTOTYPES:                                                    *
 *   void volume(double, double *, double *, double *, double *); *
 * PRE:   crankangle theta and global variables in define.h       *
 * POST:  volumes and volume derivatives have been returned       *
 ******************************************************************/
#include <math.h>
#include "define.h"
#include "adiabatic.h"

void volume(double theta, /* crank angle (radians) */
            double *ptr_vc,   /* ptr to comp. space volume */
            double *ptr_ve,   /* ptr to exp. space volume */
            double *ptr_dvc,  /* ptr to comp space volume derivative */
            double *ptr_dve)  /* ptr to exp. space volume derivative */
{

   if(myeng == 's')
      sinevl(theta, ptr_vc, ptr_ve, ptr_dvc, ptr_dve);
   if(myeng == 'y')
      yokevl(theta, ptr_vc, ptr_ve, ptr_dvc, ptr_dve);
}
/******************************************************************
 * FUNCTION: sinevl - sinusoidal volume variations and            *
 *                    derivatives                                 *
 * FILENAME volume.c                                              *
 * PROGRAMMER I.Urieli    (FORTRAN)                               *
 *            E. Malroy   (C Translation)                         *
 * DATE:      11/30/94  (FORTRAN), 03/12/96 (C Translation)       *
 * LAST MODIFIED: by I.Urieli 08/18/96                            *
 * INCLUDE:  <math.h>,"define.h"                                  *
 * GLOBAL VARIABLES: vcle, vclc, vswc, vswe, alpha                *
 * PROTOTYPE:                                                     *
 *     void                                                       *
 *     sinevl(double, double *, double *, double *, double *);    *
 * PRE:   crankangle theta, vclc, vcle, vswc, vswe & alpha        *
 * POST:  vc, ve, dvc, dve have been evaluated and returned.      *
 ******************************************************************/
void sinevl(double theta, /* crank angle (radians) */
            double *ptr_vc,   /* ptr to comp. space volume */
            double *ptr_ve,   /* ptr to exp. space volume */
            double *ptr_dvc,  /* ptr to comp space volume derivative */
            double *ptr_dve)  /* ptr to exp. space volume derivative */
{
   double vc, ve, dvc, dve; /* volumes and volume derivatives */

   vc = vclc + 0.5*vswc*(1.0 + cos(theta));
   ve = vcle + 0.5*vswe*(1.0 + cos(theta + alpha));
   dvc = -0.5*vswc*sin(theta);
   dve = -0.5*vswe*sin(theta + alpha);

   *ptr_vc = vc;
   *ptr_ve = ve;
   *ptr_dvc = dvc;
   *ptr_dve = dve;
}

/******************************************************************
 * FUNCTION: yokevl - volume variations and derivatives for Ross  *
 *   yoke drive configuration (inverted yoke) idealized to neglect*
 *   the x component of motion of the link arm to Ross yoke       *
 * FILENAME volume.c                                              *
 * PROGRAMMER                                                     *
 *            E. Malroy   (C)                                     *
 * DATE:      03/28/96 (C)                                        *
 * LAST MODIFIED: by I.Urieli 01/15/97                            *
 * INCLUDE:  <math.h>,"define.h"                                  *
 * GLOBAL VARIABLES:                                              *
 *     vclc, vcle: comp., exp. space clearance volumes (m^3)      *
 *     crank: crank radius (m)                                    *
 *     b1,b2: yoke height, base length/2 (m)                      *
 *     acomp, aexp: area of comp., exp. pistons (m^2)             *
 *     ymin: minimum yoke vertical displacement (m)               *
 * PROTOTYPE:                                                     *
 *     void                                                       *
 *     yokevl(double, double *, double *, double *, double *);    *
 * PRE:  the global variables have defined values                 *
 * POST:  vc, ve, dvc, dve have been evaluated and returned.      *
 ******************************************************************/
#include <math.h>
#include "define.h"

void yokevl(double theta, /* crank angle (radians) */
            double *ptr_vc,   /* ptr to comp. space volume */
            double *ptr_ve,   /* ptr to exp. space volume */
            double *ptr_dvc,  /* ptr to comp space volume derivative */
            double *ptr_dve)  /* ptr to exp. space volume derivative */
{
   double vc, ve, dvc, dve; /* volumes and volume derivatives */
   double sinth, costh, bth, /* local holding variables */
          yc, ye; /* yoke comp., exp side vertical displacements (m) */

   sinth = sin(theta);
   costh = cos(theta);
   bth = sqrt(b1 * b1 - (crank * costh) * (crank * costh));
   ye = crank * (sinth + (b2 / b1) * costh) + bth;
   yc = crank * (sinth - (b2 / b1) * costh) + bth;
   ve = vcle + aexp * (ye - ymin);
   vc = vclc + acomp * (yc - ymin);
   dvc = acomp*crank*(costh + (b2/b1)*sinth + crank*sinth*costh/bth);
   dve = aexp*crank*(costh - (b2/b1)*sinth + crank*sinth*costh/bth);

   *ptr_vc = vc;
   *ptr_ve = ve;
   *ptr_dvc = dvc;
   *ptr_dve = dve;
}