*HEADING
: AQUA Buoyancy and drag [T3D2H]
** Aqua loads are tested. The beam
** is kept straight and constrained, and is subject to
** buoyancy and different drag loads in different steps. For this
** simple case of a straight beam the correct total drag force
** can be calculated easily. This is measured by checking the
** reaction force at the beam nodes.
**
** i and j represent unit vectors in the 1- and z-
** directions respectively, where z represents the "upward"
** direction, i.e. the 2-direction in a 2D model and the 3-direction in
** a 3D model. Vectors vf, vp, Delta-v,
** n, and t, ap and apn have the meanings given in the
** user's manual for Aqua loads.
**
** Beam length = 10 root2
** Beam tangent,   t  =  (i + j)/root2
**
** grav=32.2,  rho_water=1.987. Steady-current velocity is
** 2 i + 1 j, and is scaled up in some of the steps.
**
** The reference height for wind is 500., and the exponent for 
** its profile is 0.2. The velocity at the reference height is
** 17.411; this produces a velocity of 20 i at
** twice the reference height.
**
*AQUA
0.,40.0,32.2,1.987
 2., 0., 1. , 0.
 2., 0., 1., 2000.
*WIND
1.987E-2,  500.,  17.411,     0.,   1.,  0.,    0.2
**   rho,     Z0,    c_x,    c_y,   dx,  dy,  alpha  
*NODE,NSET=ALL
1,   10.,   0.,  10.
3,   20.,   0.,  20.
999, 15.,   0.,  15.
*ELEMENT,TYPE=t3D2h,ELSET=ALL
1,1,3
*solid section,material=mat1,elset=all
1.0, 
*material,name=mat1
*DENSITY
1.e-14
*elastic
1.e6, 
**A negligible mass element is added to allow dynamic steps.
*ELEMENT,TYPE=MASS,ELSET=Mass
10,1
*mass,elset=mass
1E-10, 
*mpc
beam,1,999
beam,3,999
*AMPLITUDE, NAME=TEN
0.,10.,  1.,10.
*AMPLITUDE, name= A1_5
0., 1.5, 1., 1.5
*AMPLITUDE,NAME=ZERO
0.,0.,  1.,0.
********************* Node sets for loading and B.C.s
*NSET,NSET=support
999,
*NSET,nset=twist
999,
*Nset,nset=end1
1,
*nset, nset=end2
3,
*********************
*BOUNDARY
support,1,3
support,4,6
** -------------------------------------------
**     Buoyancy test in Static Step 
** -------------------------------------------
*STEP,NLGEOM
 Step A:1:  Buoyancy, PB. Total RF:  991.9 i  - 991.9 j  (v5.4 open end)
	                          :    0.0 i  -1983.8 j  (v5.5 closed end)
*STATIC
0.5,1.
*DLOAD
ALL,PB,,2.25,1.25,1.9,2500.
*EL PRINT,ELSET=ALL
 LOADS,
*ENERGY FILE
*NODE FILE
 RF, 
*EL FILE,ELSET=ALL
 LOADS,
*NODE PRINT,totals=yes
 RF, 
*END STEP
** Intermediate step; clear buoyancy load
** Without this, the buoyancy load will be
** ramped down in the drag load step.
*STEP,NLGEOM
 Intermediate step.
*STATIC
0.1,0.1
*ENERGY FILE, F=0
*NODE FILE,F=0
 RF, 
*EL FILE,ELSET=ALL,F=0
 LOADS,
*DLOAD,OP=NEW
*END STEP
** -------------------------------------------
**     Normal Drag test in Static Step
** -------------------------------------------
*STEP,NLGEOM
 Step B:3:  Normal drag, static, FDD. Total RF = -9000 i + 9000 j
                  distributed over supporting nodes.
*STATIC
.1,.2
**
**
**   vf = Delta-v =  20 i + 10 j
**    n  =  (i - j)/root2
**   1/2 rho Cd D = 9.0   
** 
** Testing: that a value of 2.0 is applied as a magnitude scaling factor
** to the drag force. (amag0=2.), and also that the force is ramped up
** over the step (there are two increments).
**
** Testing: that the steady-current velocity is being scaled up by a 
** factor of 10. using the amplitude definition TEN.
**
** Testing: that the structural velocity prescribed here
** is not taken into account when determinining
** Delta-v,  since the step is a
** static one. 
**
*BOUNDARY,type=velocity
support,1,1,10.0
support,3,3,-20.0
*DLOAD,OP=NEW
all, fdd,   2.0, 7.5491, 1.2,   0.8,  ten
**el,FDD, amag0,      D,  Cd, Alphr,  Ampc, Ampw
*NODE FILE
 RF, 
*ENERGY FILE
*EL FILE,ELSET=ALL
 LOADS,
*END STEP
**
**
** -------------------------------------------
**     Tangential Drag test in Static Step
** -------------------------------------------
**
*STEP,NLGEOM
 Step C:4: Tangential Drag, Static, FDT.  Total RF = -4929.3 i - 4929.3 j
                  distributed over supporting nodes.
*STATIC
.1,.1
**
**
**   vf = Delta-v =  20 i + 10 j
**    t  =  (i + j)/root2
**   1/2 rho pi Ct D = 0.9 
**
** Two drag loads are applied simultaneously on 
** the beam for testing purposes.
**  1st load
**   h (exponent) = 1.5
**  2nd load
**   h (exponent) = 2.0 (default)
**
**  Testing: that the exponent on the tangential drag is
**  used correctly and that it defaults to 2.
**
**
*BOUNDARY,type=velocity
support,1,1,10.0
support,3,3,-20.0
*DLOAD,OP=NEW
all, fdt,      ,  7.5491, 0.0381972,   0.8, 1.5, ten
all, fdt,      ,  7.5491, 0.0381972,   0.8,    , ten
**el,FDT, amag0,       D,        Ct, Alphr,   h, Ampc, Ampw 
*NODE FILE
 RF, 
*ENERGY FILE
*EL FILE,ELSET=ALL
 LOADS,
*END STEP
**
**
**  -------------------------------------------------------
**     Section 2 --- DYNAMIC DRAG
**  -------------------------------------------------------
**
**
** -------------------------------------------
**     Normal Drag test in Dynamic Step
** -------------------------------------------
*STEP,NLGEOM
 Step D:5: Normal drag, dynamic, FDD. Total  RF =  9000 i - 9000 j
                  distributed over supporting nodes.
*DYNAMIC
.1,.1
**  In this dynamic step the velocity of the structure
**   is taken into account, and, with the alpha parameter of 0.8,
**  the value of effective relative velocity is now
**
**           vf =    20 i + 10 j
**           vp =  12.5 i - 12.5 j, alpha=0.8
** ...  Delta-v =  10 i + 20 j
**
**
**    n  =  (i - j)/root2
**   1/2 rho Cd D = 9.0   
** 
** Testing: that the structural velocity prescribed here
** is being taken into account when determinining
** Delta-v, and that the parameter alpha is being used correctly.
**
**
** As before: the steady-current velocity is being scaled up by a 
** factor of 10. using the amplitude definition TEN.
**
**
*BOUNDARY,type=velocity
support,1,1,12.5
support,3,3,-12.5
*DLOAD,OP=NEW
all, fdd,   2.0, 7.5491, 1.2,   0.8,  ten
**el,FDD, amag0,      D,  Cd, Alphr,  Ampc, Ampw
*NODE FILE
 RF, 
*ENERGY FILE
*EL FILE,ELSET=ALL
 LOADS,
*END STEP
**
**
**
**
** -------------------------------------------
**     Tangential Drag test in DYNAMIC Step
** -------------------------------------------
**
*STEP,NLGEOM
 Step E:6: Tangential drag, dynamic, FDT. Total  RF =  -162 i - 162 j
                  distributed over supporting nodes.
*DYNAMIC
.1,.1
**
**            vf   =  2 i + 1 j
**            vp   = -2 i - 1 j, (Prescribed in BC), alpha=1.
**  
**   ... Delta-v   =  4 i + 2 j
**   ... Delta-v_t =  3 i + 3 j
**   ... Delta-v_n =  1 i - 1 j
**
**   1/2 rho pi Ct D = 0.9 
**
**   h (exponent) =  2. (default)
**
**  Testing: that in the absence of a scalimg amplitude
**  the steady-current velocity is not scaled.
**
**  Testing: that the alpha parameter defaults to 1.0.
**
*BOUNDARY,type=velocity
support,1,1,-2.0
support,3,3,-1.0
*DLOAD,OP=NEW
all, fdt,      ,  7.5491, 0.0381972,      ,   , 
**el,FDT, amag0,       D,        Ct, Alphr,  h, Ampc, Ampw 
*NODE FILE
 RF, 
*ENERGY FILE
*EL FILE,ELSET=ALL
 LOADS,
*END STEP
**
**
**
**
**
** -------------------------------------------
**     Inertial Drag test.
** -------------------------------------------
** Expected Result: total RF of  3394 i -3394 j
**                    distributed over nodes.
**
*STEP,NLGEOM
 Step F:7: Inertial drag, FI.  Total  RF =  3394 i -3394 j
                  distributed over supporting nodes.
*DYNAMIC
.1,.2
**
**        af  =  0 i + 0 j  (No waves)
**        ap  =  2 i - 6 j  (Prescribed in B.C.)
**   ...  apt = -2 i - 2 j 
**   ...  apn =  4 i - 4 j
**      rho pi D^2/4 Ca = 60.0 
**
**
**
**
*BOUNDARY,type=acceleration
support,1,1, 2.0
support,3,3,-6.0
*DLOAD,OP=NEW
all,  fi,      ,  7.4111, 0.0,   0.7 
**el, fi, amag0,   D    ,  Cm,    Ca,  Ampw
*NODE PRINT,totals=yes
rf, 
*NODE PRINT
a, 
*NODE FILE,F=2
 RF, 
*ENERGY FILE,F=2
*EL FILE,ELSET=ALL,F=2
 LOADS,
*END STEP
**
**
** Intermediate step; clear last load and
** move beam upwards so it is only half-submerged.
** 
*STEP,NLGEOM
 Intermediate step. (2)
*STATIC
0.1,0.1
*DLOAD,OP=NEW
*BOUNDARY
support, 1, 
support, 3, 3, 25.
*NODE FILE,f=0
 RF, 
*ENERGY FILE,f=0
*EL FILE,ELSET=ALL,f=0
 LOADS,
*NODE PRINT
 U,
*NODE PRINT,totals=yes
 RF, 
*END STEP
**
** ---------------------------------------------------------
**    Partial submergence test: Normal drag in dynamic step
** ----------------------------------------------------------
*STEP, NLGEOM
 Step G:9: Normal drag, dynamic, partial immersion, FDD. RF =  4500 i - 4500 j
                  distributed over supporting nodes.
*DYNAMIC
1E-6,1E-6
**
**  This load is a copy of that in Step D, but now 
**  half of the beam is submerged so  half of the
**  beam will be loaded and half of the force of step D
**  will be returned.
** 
**  NLGEOM must be active to ensure that current coordinates are used
**  in the calculations. 
**  Testing: that partial submergence is correctly handled.
**
**
*BOUNDARY,type=velocity
support,1,1,12.5
support,3,3,-12.5
*EL PRINT,ELSET=ALL 
COORD,
*DLOAD,OP=NEW
all, fdd,   2.0, 7.5491, 1.2,   0.8,  ten
**el,FDD, amag0,      D,  Cd, Alphr,  Ampc, Ampw
*NODE FILE
 RF, 
*ENERGY FILE
*EL FILE,ELSET=ALL
 LOADS,
*END STEP
**
**
**
** Intermediate step; clear last load and
** return beam to its original configuration.
** 
*STEP,NLGEOM
 Intermediate step. (3)
*STATIC
0.1,0.1
*DLOAD,OP=NEW
*BOUNDARY
support, 1, 3
*NODE FILE,F=0
 RF, 
*ENERGY FILE,F=0
*EL FILE,ELSET=ALL,F=0
 LOADS,
*END STEP
** -------------------------------------------
**     Normal End-Drag test in Dynamic Step
** -------------------------------------------
*STEP,NLGEOM
 Step H:11: End-drag, dynamic, FD1,FD2.  Total RF = - 5728 i - 5728 j
         (only load at node 1 acts)
*DYNAMIC
.1,.1
**  In this dynamic step he velocity of the structure
**   is taken into account, and, with the alpha parameter of 0.8,
**  the value of effective relative velocity is now
**
**            vf =    20 i + 10 j
**            vp =  12.5 i - 12.5 j, alpha=0.8
** ...  Delta-v  =  10 i + 20 j
** ...  Deltav_t =  15 i + 15 j
**
**   Amag 1/2 rho Cd A = 18.0   
** 
**   P = 18.0 ( 15 root2) (15 i +15 j) = 5728 (i + j)
**
** Testing: that the structural velocity prescribed here
** is being taken into account when determinining
** Delta-v, and that the parameter alpha is being used correctly.
**
** Testing: that the load force is zero when the relative velocity
** has a positive projection on the outward normal (this happens here
** at node 2.
**
** As before: the steady-current velocity is being scaled up by a 
** factor of 10. using the amplitude definition TEN.
** 
** Testing: that the force magnitude scaling factor of 2.0 is being applied.
**
*BOUNDARY,type=velocity
support,1,1,12.5
support,3,3,-12.5
*DLOAD,OP=NEW
all, fd1,   2.0, 7.5491, 1.2,   0.8,  ten
all, fd2,   2.0, 7.5491, 1.2,   0.8,  ten
**el,FDn, amag0, area,     C, Alphar,    Ampc,  Ampw
*NODE FILE
 RF, 
*ENERGY FILE
*EL FILE,ELSET=ALL
 LOADS,
*END STEP
**
**
** ---------------------------------------------------
**     Normal End-Drag test in Dynamic Step as CLOAD
** ---------------------------------------------------
*STEP,NLGEOM
 Step I:12: End-drag, dynamic, CLOAD, TFD.  Total RF = - 5728 i - 5728 j
          (only load at node 1 acts)
*DYNAMIC
.1,.1
**
** This places drag CLOADS on the two end-nodes of the beam
** equivalent to the end-drag DLOADS of step H
**
*BOUNDARY,type=velocity
support,1,1,12.5
support,3,3,-12.5
*DLOAD,OP=NEW
*CLOAD,OP=NEW
end1, tfd,   2.0, 7.5491, 1.2,   0.8,  ten
-1, 0, -1
end2, tfd,   2.0, 7.5491, 1.2,   0.8,  ten
1,0,1
**nod ,TFD, amag0, area,     Cn, Alphar,   Ampc,  Ampw
**tx,ty,tz 
*NODE FILE
 RF, 
*ENERGY FILE
*EL FILE,ELSET=ALL
 LOADS,
*END STEP
**
**
** -------------------------------------------
**     Inertial End-Drag test.
** -------------------------------------------
**
*STEP,NLGEOM
 Step J:13: Inertial End-drag, FI1, FI2.   Total RF =  - 240 i - 240 j .
*DYNAMIC
.1,.2
**
**        af  =  0 i + 0 j  (No waves)
**        ap  =  2 i - 6 j  (Prescribed in B.C.)
**   ...  apt = -2 i - 2 j 
**   ...  apn =  4 i - 4 j
**     amag rho Lts F2s  = 60.0 
**
**
**
**
*BOUNDARY,type=acceleration
support,1,1, 2.0
support,3,3,-6.0
*CLOAD,OP=NEW
*DLOAD,OP=NEW
all,  fi1,      ,      1.,    1.3, 60.3925,   0.5 
all,  fi2,      ,      1.,    1.3, 60.3925,   0.5 
**el ,FIn, amag0,     Kts,    F1s,     Lts,   F2s, Ampw
*NODE PRINT,totals=yes
rf, 
*NODE PRINT
a, 
*NODE FILE,F=2
 RF, 
*ENERGY FILE,F=2
*EL FILE,ELSET=ALL,F=2
 LOADS,
*END STEP
**
** -------------------------------------------
**     Inertial End-Drag test. -- CLOAD
** -------------------------------------------
**
*STEP,NLGEOM
 Step K:14: Inertial End-drag, CLOAD, TSI  Total RF =  -240 i - 240 j 
*DYNAMIC
.1,.2
**
** This places drag CLOADS on the two end-nodes of the beam
** equivalent to the end-drag DLOADS of step J
**
*BOUNDARY,type=acceleration
support,1,1, 2.0
support,3,3,-6.0
*DLOAD,OP=NEW
*CLOAD,OP=NEW
  end1,TSI,     ,      1.,    1.3, 60.3925,   0.5
 -1, 0, -1
  end2,TSI,     ,      1.,    1.3, 60.3925,   0.5
  1, 0, 1
**nod ,TSI, amag0,    Kts,    F1s,     Lts,   F2s, Ampw
**tx,ty,tz
*NODE FILE,F=2
 RF, 
*ENERGY FILE,F=2
*EL FILE,ELSET=ALL,F=2
 LOADS,
*END STEP
**
**
** Intermediate step; clear last load and
** return beam to its original configuration.
** 
*STEP,NLGEOM
 Intermediate step. (4)
*STATIC
0.1,0.1
*CLOAD,OP=NEW
*DLOAD,OP=NEW
*BOUNDARY
support, 1, 3
*NODE PRINT,TOTALS=YES
 RF,
 U, 
*NODE FILE,F=0
 RF, 
*ENERGY FILE,F=0
*EL FILE,ELSET=ALL,F=0
 LOADS,
*END STEP
**
**
** Intermediate step; rotate beam about
** one of its supporting nodes 90 degrees
** 
*STEP,NLGEOM
 Intermediate step. (5)
*STATIC
0.1,.5
*BOUNDARY,op=new
twist, 1,3
end2, 2
twist, 5, ,-1.570796
twist,6
*END STEP
** -----------------------------------------------------
**  End- Drag test II  in DYNAMIC Step (after rotation)
** -----------------------------------------------------
** Expected Result:  
**
*STEP,NLGEOM
 Step L:17: Transition-section buoyancy, TSB. Total RF  = 9501 i - 9501 j 
*STATIC
.1,.1
**
** Note: The t-vector is now ( - i + j ) * (-1 for node 1, 1 for second node) /root2
** 
**   Amag rho g depth area = 13.436E3 
**
**  Testing: that the load force is zero when the relative velocity
**  has a positive projection on the outward normal (this happens here
**  at node 1).
**
**  Testing: that the alpha parameter defaults to 1.0.
**
**  Testing: that the t-vector is correctly rotated for the drag end-loads.
**
*BOUNDARY,FIXED, OP=NEW
support,1,3
support,4,6
*CLOAD,OP=NEW
  end1,TSB,    1.,  7.0,  -1, 0, -1  
**nod ,TSB, amag0, area,  tx,ty,tz 
*DLOAD,OP=NEW
*NODE PRINT,TOTALS=YES
U,
RF, 
*NODE FILE
 RF, 
*ENERGY FILE
*EL FILE,ELSET=ALL
 LOADS,
*END STEP
**
*STEP,NLGEOM
 Step M:18: End-drag, dynamic, FDD. Total RF  = -12.727 i + 12.727 j 
          (only load at node 3 acts)
*DYNAMIC
.1,.1
**
** Note: The t-vector is now ( - i + j ) * (-1 for node 1, 1 for second node) /root2
** 
**            vf =  2 i + 1 j
**            vp = -2 i - 1 j, (Prescribed in BC), alpha=1.
**  
**   ... Delta-v   =   4 i + 2 j
**   ... Delta-v_t =   1 i - 1 j
**
**   Amag 1/2 rho Cd A = 9.0   
**
**  Testing: that the load force is zero when the relative velocity
**  has a positive projection on the outward normal (this happens here
**  at node 1).
**
**  Testing: that the alpha parameter defaults to 1.0.
**
**  Testing: thata the t-vector is correctly rotated for the drag end-loads.
**
*BOUNDARY,type=velocity,op=new
support,1,1,-2.0
support,2
support,3,3,-1.0
support,4,6
*CLOAD,OP=NEW
*DLOAD,OP=NEW
all, fd1,      , 7.5491, 1.2,       ,  
all, fd2,      , 7.5491, 1.2,       ,  
**el,FDn, amag0,   area,   C, Alphar,    Ampc,  Ampw
*NODE FILE
 RF, 
*ENERGY FILE
*EL FILE,ELSET=ALL
 LOADS,
*END STEP
**
**
** -----------------------------------------------------
**  End- Drag test II  in DYNAMIC Step (after rotation) - CLOAD
** -----------------------------------------------------
** Expected Result:  RF of -12.727 i + 12.727 j for each end-node
**
*STEP,NLGEOM
 Step N:19: End-drag, dynamic, CLOAD, TFD.  Total RF  = - 12.727 i + 12.727 j 
          (only load at node 3 acts)
*DYNAMIC
.1,.1
** 
**
** This places drag CLOADS on the two end-nodes of the beam
** equivalent to the end-drag DLOADS of step M
**
**  Testing: that the alpha parameter defaults to 1.0.
**
**  Testing: that the t-vector is correctly rotated in the drag CLOADS 
**
*BOUNDARY,type=velocity,op=new
support,1,1,-2.0
support,2
support,3,3,-1.0
support,4,6
*DLOAD,OP=NEW
*CLOAD,OP=NEW
 end1, tfd,      , 7.5491,   1.2,      
-1, 0, -1
 end2, tfd,      , 7.5491,   1.2,   
 1,0,1
**nod ,TFD, amag0,   area,    Cn, Alphar,   Ampc,  Ampw
**tx,ty,tz 
*NODE FILE
 RF, 
*ENERGY FILE
*EL FILE,ELSET=ALL
 LOADS,
*END STEP
**
**
**
**
** Intermediate step; clear last load and
** place centre of beam 1000 units above water level.
** 
** Centre of beam must move up from 15 j to 1040 j.
*STEP,NLGEOM
 Intermediate step. (6)
*STATIC
0.1,0.1
*CLOAD,OP=NEW
*DLOAD,OP=NEW
*BOUNDARY,op=new
twist, 3,  , 1025
*BOUNDARY,FIX,op=new
twist,1,2
twist,4,6
*NODE FILE,F=0
 RF, 
*ENERGY FILE,F=0
*EL FILE,ELSET=ALL,F=0
 LOADS,
*END STEP
**
**
*STEP,NLGEOM
 Step O:21: Wind-drag, dynamic, WDD.   Total RF  = -520.2 (i +  j) 
*DYNAMIC
.01,.01
** Note: The t-vector is now ( - i + j ) * (-1 for node 1, 1 for second node)
** The current height is twice the reference height for the wind,  2*500 above still
** water level.
**            vf =  cx (1000/500)^0.2 *Ampx= 20.0 * Ampx
**            vf =  30 i +  0 j (Ampx=1.5)
**      alpha vp =  -2 i - 2 j, (Prescribed in BC), alpha=0.5
**  
**   ... Delta-v   =  32 i + 2 j
**   ... Delta-v_t =  15 i - 15 j
**   ... Delta-v_n =  17 i + 17 j 
**
**   Amag 1/2 rho Cd A = 9.0 E-2   
**
**  Testing: that the height-dependence of the wind is being correctly done.
**
**  Testing: that the alpha parameter is correctly used.
** 
*BOUNDARY,type=velocity,op=new
support,1,1,-4.0
support,2
support,3,3,-4.0
support,4,6
*CLOAD,OP=NEW
*DLOAD,OP=NEW
**el,WDD, amag0,      D,  Cd, Alphr,  Ampx, Ampy
all, wdd,      , 7.5491, 1.2,   0.5,  A1_5, zero
*NODE PRINT,NSET=ALL, TOTALS=YES
 U,
 RF,
 V, 
 RF,
*NODE FILE
 RF, 
*ENERGY FILE
*EL FILE,ELSET=ALL
 LOADS,
*END STEP
**
** -------------------------------------------
**     Wind End-Drag test in Dynamic Step
** -------------------------------------------
*STEP,NLGEOM
 Step P:22: Wind End-drag, dynamic, WD1, WD2.  Total RF = -28.63 i + 28.63 j 
           (only load at node 3 acts)
*DYNAMIC
.01,.01
** Note: The t-vector is now ( - i + j ) * (-1 for node 1, 1 for second node)/root2
** 
**            vf =  20 i + 0 j ( as in step N but now Ampx=1 (default)
**            vp = -20 i - 10 j, (Prescribed in BC), alpha=1.
**  
**   ... Delta-v   =   40 i + 10 j
**   ... Delta-v_t =   15 i - 15 j
**
**   Amag 1/2 rho C A = 9.0 E-2   
**
**  Testing: that the load force is zero when the relative velocity
**  has a positive projection on the outward normal (this happens here
**  at node 1).
**
**  Testing: that the alpha parameter defaults to 1.0.
**
**  Testing: that the t-vector is correctly rotated for the drag end-loads.
**
**  Testing: that the default value for the amplitude Ampx is 1.0
** 
*BOUNDARY,type=velocity
support,1,1,-20.0
support,3,3,-10.0
*CLOAD,OP=NEW
*DLOAD,OP=NEW
all, wd1,      , 7.5491, 1.2,       ,
all, wd2,      , 7.5491, 1.2,       , 
**el,WDn, amag0,   area,   C, Alphar,    Ampx,  Ampy
*NODE FILE
 RF, 
*ENERGY FILE
*EL FILE,ELSET=ALL
 LOADS,
*END STEP
**
**
** -------------------------------------------
**     Wind End-Drag test in Dynamic Step - CLOADS
** -------------------------------------------
*STEP,NLGEOM
 Step Q:23: Wind End-drag, dynamic, CLOAD, TWD.  Total RF = -28.63 i + 28.63 j 
          (only load at node 3 acts)
*DYNAMIC
.01,.01
**
** This places drag CLOADS on the two end-nodes of the beam
** equivalent to the end-drag DLOADS of step P
**
**
**  Testing: that the load force is zero when the relative velocity
**  has a positive projection on the outward normal (this happens here
**  at node 1).
**
**  Testing: that the alpha parameter defaults to 1.0.
**
**  Testing: that the t-vector is correctly rotated for the drag end-loads.
**
**  Testing: that the default value for the amplitude Ampx is 1.0
** 
*BOUNDARY,type=velocity,op=new
support,1,1,-20.0
support,2,2
support,3,3,-10.0
support,4,6
*DLOAD,OP=NEW
*CLOAD,OP=NEW
 end1, twd,      , 7.5491,   1.2,      
-1, 0, -1
 end2, twd,      , 7.5491,   1.2,   
 1,0,1
**nod,TWD,  amag0,   area,     Cn, Alphar,   Ampx,  Ampy
**tx,ty,tz 
*NODE FILE
 RF, 
*ENERGY FILE
*EL FILE,ELSET=ALL
 LOADS,
*END STEP
**
**
**