For the description of transfer processes in separated turbulent two-phase flow, knowledge is necessary about interactions at the interface. Particularly experimental studies were performed of the two-phase-friction coefficient, film thickness, entrainment and heat transfer for adiabatic and condensing conditions. Working systems were n-heptane/air, water/air and condensing n-heptane. The measurement of the liquid film thickness was successful with the ultrasonic method and the entrainment was measured with an isokinetic technique. Quantitative connections between hydrodynamic parameters were discussed and compared with literature models. Based on experimental data, special models are proposed. Partly the influence of the mass transfer intensity cannot be neglected for calculation of the two-phase-friction coefficient. For the description of the heat transfer for film condensation in turbulent flow the interface shear stress and the inclination angle of the tube have proved useful.