Forces on flapping or rotating wings, like flapping wings of micro air vehicles or blades of wind turbines are of great interest to engineers. To investigate the ways birds and insects fly, forces created by flapping wings are of importance to biologists. The pressure field, combined with the velocity field, gives a complete description of the (incompressible) flow dynamics. Furthermore the pressure field is the main contributor to the aerodynamic loading of bodies immersed in the fluid. Traditional techniques to determine pressure and forces rely on the determination of surface pressure and integral loads by point pressure and force balance measurements. In situations where it is difficult (or impossible) to instrument the body, using particle image velocimetry (PIV) velocity data to determine forces and pressure poses an interesting alternative to the existing approaches to determine sectional loading. 德國(guó)LaVision PIV/PLIF粒子成像測(cè)速場(chǎng)儀 三維立體PIV 自適應(yīng)粒子成像測(cè)速場(chǎng)儀（PIV） 體視層析粒子成像測(cè)速系統(tǒng)(Tomo-PIV) 時(shí)間分辨粒子成像測(cè)速系統(tǒng)(TR-PIV)