When the throttle is opened wide, the engine velocity raises, and also the pump moves more quickly projecting the oil toward the turbine. Inside of a torque converter there are actually at the least a few rotating components: the impeller, and that is mechanically driven because of the key mover; https://torqueconverterclutch97418.blogoscience.com/40248068/the-basic-principles-of-torque-converter-clutch