Measuring slip in flowing fluids

Research by Drs Vince Craig, David Williams and Chiara Neto from the Australian National University, has revealed that "when liquids flow at relatively fast speeds in a confined space, the liquid molecules adjacent to the surface are in fact moving", Dr Craig said. The research was conducted using an Atomic Force Microscope, which has a very small ball attached to a sensing spring that measures the forces on the ball produced by the liquid as it approaches a solid surface.

This result will have implications in many fields, including extracting oil from rocks, blood flow through narrow capillaries and nanotechnology. As being able to calculate the slip will allow future experiments to be controlled more accurately. Further experiments are planned to determine what features of different surfaces effect slippage, so that even greater control will be available in experiments.