Investigation of non-ideal gas flows around a circular cylinder

The aerodynamic performance of a cylinder Pitot probe for velocity measurements in compressible non-ideal gas flows, such as those encountered Organic Rankine Cycle (ORC) turbines, is investigated by means Computational Fluid Dynamics. Numerical simulations are performed at subsonic and transonic conditions, freestream Reynolds numbers the critical regime. working fluid organic vapour Novec™ 649. Air flow similar inlet conditions reported comparison. Steady unsteady RANS solutions computed with Spalart–Allmaras turbulence model. results assessed against experimental collected wind tunnel. URANS good agreement data all considered delivers reasonably accurate estimations back pressure. Using dense leads to lower minimum pressure coefficient compared air, alongside reduced maximum Mach number due speed sound behaviour. In experimentally studied range compressibility factors numbers, discrepancies observed respect air mostly an effect different isentropic exponents. regime, shock waves causing boundary layer separation weakened gas, but also decreased, contributing rising form drag.