| 22 | 22 | 2. In the other scenario, it is purely an effect of the radial expansion of gas away from the collision region. The infinite case teaches us that the velocity goes to zero in the center of the collision region in the MHD case. However, when there is a pressure gradient between the collision region and the surrounding ambient gas, we see a strong outward (relative to the center of the collision region) velocity field arise. That there is now an up/down (relative to the cylindrical axis of the flows) velocity field within the collision region, sends gas upward and downward, thus effectively straightening out the collision region. In the hydro case, this is not the case, as there the velocity field is the usual sheared flow field. (Which, by the way, uh-oh for our runs declaring to study a 'shear' effect). Thus, we do not see a realignment of the interface in the hydro case. In visit, drawing a line along the original collision angle shows supports that the interface realligns in the MHD case, but not in the hydro case. |
