Abstract
This paper numerically studies the performance of a 2D CoFlow Jet cylinder wind sail at different angle of attack and jet strength. The cylinder sail is simulated using the in-house Reynolds-averaged Navier-Stokes (RANS) solver, FASIP, with Spalart-Allmaras (SA) turbulence model. A 3rd order WENO scheme is used to resolve the Navier-Stokes equations. The dual-time step method is used for unsteady simulation. A comparative analysis of the lift coefficients, drag coefficients and energy expenditure at various jet momentum coefficients and angles of attack are conducted. When C-mu = 0.5, the lift coefficient at zero angle of attack reaches 12.63. The power coefficient at this flow condition is only 5% of CL, resulting in a C-L/C-D,(c) of 19.92. When C-mu is increased to 2.0, the lift coefficient reaches 25.13, about doubled, but the power coefficient is increased exponentially by 10 times. As AoA varies from -90 degrees to 90 degrees, the lift does not vary much within AoA of +/- 20 degrees at high CL level of 20. At a lower CL level of 12, the CL has a much broader insensitive range to AoA from -20 degrees to +60 degrees. The drag coefficient and CFJ power coefficients are also similar. The numerical results of 2D CFJ cylinders indicate that the CFJ cylinder has the potential to provide very high lift coefficient at low drag and low power consumption with a large tolerance range of AoA. Such features are very beneficial as rigid wind sails for shipping.