INSTANTANEOUS DRAG AREA, VELOCITY, OPENING SHOCK FORCE, AND DISTANCE OF FALL OF A PARACHUTE DEPLOYED IN VERTICAL FALL.

ludtke 1987.f

* AD-A180 901
* NOTES ON A PARACHUTE OPENING FORCE
* ANALYSIS APPLIED TO A VERTICAL
* TOWARD-THE-EARTH TRAJECTORY
* BY WILLIAM P. LUDTKE
* UNDERWATER SYSTEMS DEPARTMENT
* 28 MAY 1987

* inputs:
* 1
* 0.0022
* 340
* 722
* 0.91
* 200
* 6
* 400   
* 962   
* 1.46  
* 1.15 
* 0.632 
* 4700

C cctbx_project/compcomm/newsletter09/sf_times.py, svn rev. 9983
C cos_wrapper, exp_wrapper replaced with COS, SIN, EXP

      program run
      REAL*4 N
      t0den=100.000
5     print *, 'INPUT IOPT'
      read(5,*,END=100) IOPT
      print *, 'input rho, vs, cdso, t0, w, j'
      read(5,*)rho,vs,cdso,t0,w,j
      if(iopt .eq. 2) go to 3
      print *, 'input amo,aso,xk,cp,n,v0'
      read(5,*)amo,aso,xk,cp,n,v0
3     dt=t0/t0den
      tau=0
      g=32.2
      s=0.
      x=tau
      cds=tau*cdso
      fs=.5*rho*vs**2*cdso
      f=tau*fs
      vol=0
      ipass=0
      dt=10.*dt
      if(iopt .eq. 2) go to 8
7     v=vs
      vol=0
      t=0
      xm=(2.*w)/(rho*g*cdso*vs*t0)
6     dv=(g-v**2/(xm*vs*t0)*(t/t0)**j)*dt
      dvol=(v*amo*(t/t0)**j-aso*(t/t0)**j*xk*(cp*rho/2)**n *v**(2.
     & *n))*dt
      vol=vol+dvol
      v=v+dv
      t=t+dt
      if(t .ge. t0) go to 4
      go to 6
4     write(6, '(2(1x,f12.6))') t0, vol
      if(vol .gt. (v0-10.) .and. vol .lt. (v0+10.)) go to 8
      t0=t0*(v0/vol)
      ! write(6, '(2(1x,f12.6))') t0, vol
      if(ipass .gt. 500) stop
      ipass=ipass+1
      go to 7
8     continue
      t=0
      v=vs
      dt=dt/10
      write(6,10) rho,vs,cdso,w,t0,xm,j,fs
10    format(1H1, 'density='1PE12. 5, 2X,'v(s)='0PF8. 1, 2X, 'cdso='0PF8. 2
     1  ,2X, 'w='F7. 1, 2X,'t(0)='F6. 3, 2X, 'M='1PE12. 5, 2X, 'J='I2,2x
     2  ,'FS='1PE12. 5)
      if(IOPT .eq. 1) write(6,11) amo,aso,xk,cp,n,v0,vol
11    format(1H0,4x,'amo=',0PF8. 2, 7x,'aso=', 0PF8.2, 5x,'k=',0pf8.3
     4  ,1x,'CP=',0PF7.3, 5x, 'n=',0pf6.3,1x,'v0=',1pe12. 5,7x
     5  ,'vol='1pe1 2.5)
      write(6,20)
20    format(1H0,2x,'time='2x,'time ratio',2x,'vel ratio',2x
     1  ,'drag area ratio',2x,'shock factor',3x,'shock force',2x,'dist of
     2  fall')
30    format(1x,f6.2,2f12.5,f17.7,1p2e14.5,0pf15.2)
      lcount=5
35    if(t/t0 .gt. 1.51) GO TO 5
      if(lcount .lt. 54) go to 38
      write(6,37)
37    format(1h1)
      write(6,20)
      lcount=3
38    lcount=lcount+1
      write(6,30) t,t/t0,v/vs,cds/cdso,x,f,s
      told=t+.02
      if(dt .gt. 0.02) told=t+dt
40    t=t+dt
      if(t .gt. told)t=told
      tovto=(1-tau)*(t/t0)**j+tau
      cds=cdso*tovto
      dv=(g-v**2*tovto/(xm*vs*t0))*dt
      ds=v*dv/(g-v**2*tovto/(xm*vs*t0))
      v=v+dv
      s=s+ds
      x=(v/vs)**2*cds/cdso
      f=x*fs
      if(t .lt. told) go to 40
      go to 35
100     STOP
      end