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RECONNECTION: Implement one more type of perturbation.

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This perturbation is similar to the magnetic field one, but
applied to the velocity field.

Also allow the user to choose the perturbation type through the
parameter 'perturbation'.

Signed-off-by: Grzegorz Kowal <grzegorz@amuncode.org>
This commit is contained in:
Grzegorz Kowal 2017-03-28 23:23:50 -03:00
parent c7e0cb92d2
commit 6599e4e54f
1 changed files with 52 additions and 21 deletions
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41
src/user_problem.F90
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@ -53,6 +53,7 @@ module user_problem
real(kind=8), save :: bper = 0.00d+00
real(kind=8), save :: bgui = 0.00d+00
real(kind=8), save :: vper = 1.00d-02
real(kind=8), save :: kper = 1.00d+00
real(kind=8), save :: xcut = 4.00d-01
real(kind=8), save :: ycut = 1.00d-02
real(kind=8), save :: yth = 1.00d-16
@ -60,6 +61,7 @@ module user_problem
real(kind=8), save :: pmag = 5.00d-01
real(kind=8), save :: blim = 1.00d+00
real(kind=8), save :: zeta = 0.00d+00
integer , save :: pert = 1
! flag indicating if the gravitational source term is enabled
!
@ -104,6 +106,7 @@ module user_problem
! local variables
!
character(len=64) :: problem_name = "none"
character(len=64) :: perturbation = "noise"
!
!-------------------------------------------------------------------------------
!
@ -124,7 +127,19 @@ module user_problem
! get the problem name
!
call get_parameter_string("problem", problem_name)
call get_parameter_string("problem" , problem_name)
call get_parameter_string("perturbation", perturbation)
! choose the perturbation type
!
select case(perturbation)
case('noise', 'random')
pert = 1
case('vel', 'velocity_mode')
pert = 2
case('mag', 'magnetic_mode')
pert = 3
end select
! get the reconnection problem parameters
!
@ -134,6 +149,7 @@ module user_problem
call get_parameter_real("bper" , bper)
call get_parameter_real("bgui" , bgui)
call get_parameter_real("vper" , vper)
call get_parameter_real("kper" , kper)
call get_parameter_real("xcut" , xcut)
call get_parameter_real("ycut" , ycut)
call get_parameter_real("yth" , yth )
@ -238,7 +254,7 @@ module user_problem
use equations , only : idn, ivx, ivy, ivz, ipr, ibx, iby, ibz, ibp
use equations , only : csnd2
use operators , only : curl
use random , only : randomn
use random , only : randomn, randomu
! local variables are not implicit by default
!
@ -251,7 +267,7 @@ module user_problem
! local variables
!
integer :: i, j, k
real(kind=8) :: yt, yp, yl, yu
real(kind=8) :: xp, yp, yt, yl, yu
real(kind=8) :: yrat, itanh
real(kind=8) :: vx, vy, vz, vv
@ -289,7 +305,7 @@ module user_problem
! calculate the perturbation of magnetic field
!
if (bper /= 0.0d+00) then
if (bper /= 0.0d+00 .and. pert == 3) then
! initiate the vector potential (we use velocity components to store vector
! potential temporarily, and we store magnetic field perturbation in U)
@ -350,7 +366,7 @@ module user_problem
! add the magnetic field perturbation
!
if (bper /= 0.0d+00) then
if (bper /= 0.0d+00 .and. pert == 3) then
q(ibx,1:jm) = q(ibx,1:jm) + pdata%q(ibx,i,1:jm,k)
q(iby,1:jm) = q(iby,1:jm) + pdata%q(iby,i,1:jm,k)
q(ibz,1:jm) = q(ibz,1:jm) + pdata%q(ibz,i,1:jm,k)
@ -384,6 +400,7 @@ module user_problem
! set the random velocity field near the current sheet
!
if (pert == 1) then
if (abs(x(i)) <= xcut) then
do j = 1, jm
if (abs(y(j)) <= ycut) then
@ -412,6 +429,20 @@ module user_problem
end if ! |y| < ycut
end do ! j = 1, jm
end if ! |x| < xcut
end if ! pert == 1
if (pert == 2) then
xp = pi2 * kper * (x(i) + 0.5d+00)
do j = 1, jm
yp = y(j) / pth
vx = (2.0d+00 * yp * tanh(yp) - 1.0d+00 / cosh(yp)**2) &
* exp(- yp**2) * sin(xp) / (pi2 * kper * pth)
vy = tanh(yp) * exp(- yp**2) * cos(xp)
q(ivx,j) = vper * vx
q(ivy,j) = vper * vy
end do ! j = 1, jm
end if ! pert == 2
! convert the primitive variables to the conservative ones
!