binary_omegaana.C

/*
 * Methods of class Binary to set analytical value to omega
 *
 */

/*
 *   Copyright (c) 2004 Francois Limousin
 *
 *   This file is part of LORENE.
 *
 *   LORENE is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   LORENE is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with LORENE; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */


char binary_omegaana_C[] = "$Header: /cvsroot/Lorene/C++/Source/Binary/binary_omegaana.C,v 1.3 2004/03/25 10:29:01 j_novak Exp $" ;

/*
 * $Id: binary_omegaana.C,v 1.3 2004/03/25 10:29:01 j_novak Exp $
 * $Log: binary_omegaana.C,v $
 * Revision 1.3  2004/03/25 10:29:01  j_novak
 * All LORENE's units are now defined in the namespace Unites (in file unites.h).
 *
 * Revision 1.2  2004/01/20 15:21:52  f_limousin
 * First version
 *
 *
 * $Header: /cvsroot/Lorene/C++/Source/Binary/binary_omegaana.C,v 1.3 2004/03/25 10:29:01 j_novak Exp $
 *
 */

// Headers C
#include "math.h"

// Headers Lorene
#include "binary.h"
#include "unites.h"


void Binary::analytical_omega() {
  
  using namespace Unites ;
    
    double rr = separation() ;
    double mtot = star1.mass_g() + star2.mass_g() ; 

    // Compacity factor
    double compact = ggrav * mtot / rr ; 

    double omega2 ; 
    
    if ( star1.is_irrotational() ) {
    
        // Irrotational case
        // -----------------
    
    assert( star2.is_irrotational() ) ; 
    
    omega2 = ggrav * mtot / pow(rr, 3) 
        * (1. - 2.75 * compact + 8.625 * compact*compact ) ; 
    
    }
    else{   // Corotating case
        // ---------------
    
    assert( !star2.is_irrotational() ) ; 
    
    // a0/R
    double a0sr = star1.ray_eq() / rr ; 

    // Rescaled moment of inertia 5 I / (2 M a0^2)
    double ired = double(5)/double(3) * ( 1. - double(6) / M_PI / M_PI ) ; 
    omega2 =  ggrav * mtot / pow(rr, 3)
        * (1. - compact * ( 2.75 + 2.*a0sr*a0sr * ired 
          - 0.48*pow(a0sr, 4) * ired*ired ) 
          + compact*compact * ( 8.625 + 2.75*a0sr*a0sr * ired
                    + 2.*pow(a0sr, 4) * ired*ired ) ) ;
    
    }    
    
    omega = sqrt( omega2 ) ; 
    
    // The derived quantities are obsolete:
    del_deriv() ; 
    
}

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