Reynolds-Averaged Navier-Stokes Codes and Marine Propulsor Analysis

This report describes the application of Reynolds-Averaged Navier- Stokes RANS codes to viscous-flow problems associated with marine propulsors. The theory behind RANS codes is described, and the numerical solution methods typically applied to solve the RANS equations are discussed. A description of the strengths and limitations of applying RANS codes to predict real fluid effects is given. Careful scrutiny and engineering judgment must be exercised in the interpretation of predictions based on the turbulence models typically embodied in RANS codes. Two benchmark computations using DTNS3D, a typical RANS code, are presented to illustrate interpretation concerns. The examples include flow over a pipe expansion and flow over the leading edge of a blunt rectangular plate.