Because the turbine speed lags continuously at the rear of the impeller (pump) velocity, the velocity ratio is lower than 1. Because of this There may be friction in the transmission fluid which results in electrical power losses. Within the casing, fluid is pushed by centrifugal force in the pump. https://torque-converter-clutch63185.izrablog.com/34486117/torque-converter-clutch-no-further-a-mystery