Measurement of Near Wall Fluid Interaction with an Atomised Spray

The amount of research involving the effects of fluid interaction with solid boundaries has been provided by a large number of authors. However, these primarily involve single phase flow with uniform and controlled inlets. This study studies the techniques of non-intrusive optical measurement to visualise and measure the spanwise wake flow of various cylinders with modified surface geometry. This is to establish the ability of high magnification PIV and the effects of surface configurations on the near wake region within complex and multiphase flow. The measurement and visualisation is carried out using Particle Image Velocimetry (PIV). Through visualisation it was observed that smaller droplets are entrained into the recirculation region behind the cylinder while the larger droplets impact the cylinder surface, accumulate and drip off, and/or rebound off the surface and disperse into the free stream. The flow over the cylinder resulted in the formation of a wet layer within recessed geometry i.e., the grooves and riblets. PIV enables near wake flows to be visualised. Due to the limitations of 2D PIV seeded laden droplets travelling in/out of the plane are poorly represented. This is especially noticed when correlating images of helical type surface geometry. The use of high magnification PIV allows resolving smaller flow features within a complex flow regime. The measurements can fully identify and quantify flow within surface changes.