I’m currently using version 2.2.0 of ASPECT and I’m trying to model a plume whose path is driven by mantle flow (see Steinberger et al. (2019): Yellowstone Plume Conduit Tilt Caused by Large-Scale Mantle Flow, esp. figure 3 and 4). In order to achieve this I’d like to implement a velocity field split in two, namely a left-oriented velocity field in the lower part of the figure and a right-oriented velocity field in the upper part of the figure, using the function Prescribed Velocity Boundary Indicators. However, in the simulation, the plume immediately gets dragged to the right and the effect of the lower boundary condition just described is not really visible anymore and, in addition, the setup leads to multiple convection cells I didn’t aim for. Below you can find the code I used.
Do you have any ideas what I can do in order to see the effect of both velocity field directions on the plume, both in the left and in the right direction? Thank you in advance for your answers!
set Dimension = 2 set Start time = 0 set End time = 2e7 set Use years in output instead of seconds = true #set Maximum time step = 1e7 set Output directory = NGP-vm5a set Use conduction timestep = true subsection Geometry model set Model name = box subsection Box set X repetitions = 4 set Y repetitions = 1 set X extent = 12e6 set Y extent = 3e6 end end ##################### Boundary conditions subsection Boundary velocity model set Prescribed velocity boundary indicators = left x: function , right x: function subsection Function set Variable names = x,y set Function constants = cm=0.1 set Function expression =if(y<1.5e6, -0.45*cm, 0.45*cm); 0 end set Zero velocity boundary indicators = bottom end subsection Boundary temperature model set Fixed temperature boundary indicators = bottom, top set Model name = box subsection Box set Top temperature = 1600 set Bottom temperature = 4000 end end subsection Initial temperature model set Model name = function subsection Function set Variable names = x,z set Function expression = 3100 - z*0.5e-3 + if (x>9.5e6 & x<10e6 & z<0.5e6,2000,0) end end subsection Material model set Model name = multicomponent subsection Multicomponent set Densities = 3300,3600 set Viscosities = 1e21,1e22 set Viscosity averaging scheme = harmonic end end ## Use compositional field to simulate a lower mantle of different composition subsection Compositional fields set Number of fields = 1 end subsection Initial composition model set Model name = function subsection Function set Variable names = x,z set Function expression = 1 end end subsection Gravity model set Model name = vertical subsection Vertical set Magnitude = 10.0 end end subsection Heating model set List of model names = shear heating end subsection Mesh refinement set Initial adaptive refinement = 0 set Initial global refinement = 5 set Time steps between mesh refinement = 10 set Strategy = temperature,density end subsection Postprocess set List of postprocessors = visualization subsection Visualization set Number of grouped files = 0 set Output format = vtu set List of output variables = density,viscosity,heating set Time between graphical output = 1e5 set Interpolate output = true end end