Impact of Marangoni effects on the apparent contact angle — a numerical investigation

The influence of thermocapillary stress on the shape of the gas-liquid phase boundary is investigated numerically. We consider the case of a cold liquid meniscus at a heated solid wall in the absence of gravity. An "apparent contact angle" is defined geometrically and the deviation of this apparent contact angle from the prescribed static contact angle due to thermocapillary convection is studied. We observe an enlarged apparent contact angle compared to the isothermal case. Since a fixed static contact angle is used in the computations, we emphasize that this effect does not depend on the specific model of a dynamic contact angle.