Wall shear stress or skin friction causes a significant amount of drag in an aerodynamic system. As a result, measurements are extremely important for efficient and effective aerodynamic design as well as fundamental understanding of the underlying flow physics. This measurement is also important for a wide variety of applications ranging from feedback flow control to drag reduction to wind tunnel design and characterization. It may also be a useful technique for non‐intrusive flow rate measurement. An instrument grade, time accurate sensor with sufficient spatial resolution is required for quantitative time resolved wall shear stress measurement. This chapter gives an overview of relevant measurement scales that depend on the nature of the flow, existing measurement techniques with their strengths and limitations, and a methodology to characterize shear stress sensors, ultimately leading to a fully characterized shear stress measurement tool.
