It has to flow in opposite directions to keep a balanced concentration therefore a balanced diffusion. If it went in the same direction as the blood there would be less diffusion as, for instance, by the time the dialysis fluid from the right side got the the left, no more diffusion could take place with the blood above it as the fluid would already have gone though diffusion with blood further back down the right end so particles would not move from a high concentration to a low concentration as the fluid below would have a high concentration too from what it gained back at the right end.
opposite flow
Viscisity
Narmada river
river watershed
These terms are usually used in conjuction with fluid-fluid heat exchangers. In both cases, the two fluids in the exchanger are moving in parallel flowpaths with each other. In contraflow, the fluids move in opposite directions along those paths, so the two inlets are on opposite ends of the exchanger. In parallel flow, the fluids move in the same direction, so the inlets are on the same end.
Gas outflows often in two opposite directions because of stars magnetic field.
The flow path of a heated liquid will vary. For the in cross-flow heat the liquid path is perpendicular to each other but in counter-current heat,the liquids flow in opposite directions.
the directions are opposite to each other
the directions are opposite to each other
The currents flow in opposite directions due to the Coriolis effect.
during dialysis the blood is is flowin through a closed system
fluid friction or drag pushes the opposite direction the wnd is trying to flow.