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Combining ij - ji collisions

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In an attempt to make the operator fully conservarive I have combined ij
and ji collisions (when i/=j).

Now the matter is to find a way that makes this conserve momentum and
energy for intraspecies.
This commit is contained in:
Jorge Gonzalez 2023-07-12 15:17:26 +02:00
commit c3a6f77ffc
2 changed files with 98 additions and 0 deletions
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94
src/modules/mesh/moduleMesh.f90
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@ -967,6 +967,7 @@ MODULE moduleMesh
INTEGER:: i, j
INTEGER:: n
INTEGER:: t
INTEGER:: p
TYPE(lNode), POINTER:: partTemp
INTEGER(8), ALLOCATABLE:: cellNodes(:)
CLASS(meshNode), POINTER:: node
@ -985,6 +986,8 @@ MODULE moduleMesh
REAL(8):: deltaW_par, deltaW_par_square, deltaW_per_square !Increments of W
REAL(8):: theta_per !Random angle for perpendicular direction
REAL(8):: eps = 1.D-12
REAL(8):: preV(1:3), totalP_ij(1:3), totalP_ji(1:3)
REAL(8), ALLOCATABLE:: deltaV_ji(:,:)
!$OMP DO SCHEDULE(DYNAMIC) PRIVATE(partTemp)
@ -1012,6 +1015,7 @@ MODULE moduleMesh
END DO
totalP_ij = 0.D0
!Loop over particles of species_i
partTemp => cell%listPart_in(i)%head
DO WHILE(ASSOCIATED(partTemp))
@ -1071,7 +1075,9 @@ MODULE moduleMesh
W(3) = normC + deltaW_par + deltaW_par_square
!Update particle velocity and return to laboratory frame
preV = partTemp%part%v
partTemp%part%v = MATMUL(rotation, W) + velocity
totalP_ij = totalP_ij + pair%sp_i%m*(partTemp%part%v - preV)
END DO
@ -1080,6 +1086,94 @@ MODULE moduleMesh
END DO
!Do corresponding collisions
IF (i /= j) THEN
!Do scattering of particles from species_j due to species i
!Compute background properties of species_i
DO n = 1, cell%nNodes
node => self%nodes(cellNodes(n))%obj
CALL calculateOutput(node%output(i), output, node%v, pair%sp_i)
densityNodes(n) = output%density/n_ref
velocityNodes(n,1:3) = output%velocity(1:3)/v_ref
temperatureNodes(n) = output%temperature/T_ref
END DO
totalP_ji = 0.D0
ALLOCATE(deltaV_ji(1:cell%listPart_in(j)%amount,1:3))
!Loop over particles of species_j
partTemp => cell%listPart_in(j)%head
p = 1
DO WHILE(ASSOCIATED(partTemp))
density = cell%gatherF(partTemp%part%Xi, cell%nNodes, densityNodes)
velocity = cell%gatherF(partTemp%part%Xi, cell%nNodes, velocityNodes)
temperature = cell%gatherF(partTemp%part%Xi, cell%nNodes, temperatureNodes)
!If cell temperature is too low, skip particle to avoid division by zero
IF (temperature>eps) THEN
l2 = pair%l2_i/temperature
l = SQRT(l2)
ELSE
partTemp => partTemp%next
CYCLE
END IF
A = pair%A_j*density
!Do the required substeps
DO t = 1, pair%nSubSteps
C = partTemp%part%v - velocity
normC = NORM2(C)
!C_3 = z; C_1, C2 = x, y (per)
C_per = NORM2(C(1:2))
cosPhi = C(1) / C_per
sinPhi = C(2) / C_per
cosThe = C(3) / normC
sinThe = C_per / normC
!Rotation matrix to go from W to C
rotation = RESHAPE((/ cosThe*cosPhi, cosThe*sinPhi, -sinThe, & !First column
-sinPhi, cosPhi, 0.D0, & !Second column
sinThe*cosPhi, sinThe*sinPhi, cosThe /), & !Third column
(/ 3, 3 /))
!W at start is = (0, 0, normC), so normW = normC
lW = l * normC
GlW = G(lW)
HlW = H(lW)
AW = A / normC
!Calculate changes in W due to collision process
deltaW_par = - A * pair%one_plus_massRatio_ij * l2 * GlW * pair%tauSub
deltaW_par_square = SQRT(AW * GlW * pair%tauSub)*randomMaxwellian()
deltaW_per_square = SQRT(AW * HlW * pair%tauSub)*randomMaxwellian()
!Random angle to distribute perpendicular change in velocity
theta_per = PI2*random()
!Change W
W(1) = deltaW_per_square * COS(theta_per)
W(2) = deltaW_per_square * SIN(theta_per)
W(3) = normC + deltaW_par + deltaW_par_square
preV = partTemp%part%v
partTemp%part%v = MATMUL(rotation, W) + velocity
totalP_ji = totalP_ji + pair%sp_j%m*(partTemp%part%v - preV)
END DO
!Move to the next particle in the list
partTemp => partTemp%next
END DO
END IF
print *, k, NORM2(totalP_ij), NORM2(totalP_ji)
END DO
DEALLOCATE(densityNodes, velocityNodes, temperatureNodes, cellNodes)