Computational study of lenticular airship with and without propeller

Abstract

This thesis examines the aerodynamic characteristics and flight dynamics of a lighter-than-air airship using computational fluid dynamics (CFD). The flow field around a lenticular airship, which is known to have poor aerodynamic characteristics, with blowing of propeller is calculated on the basis of the Reynolds-averaged Navier-Stokes equations with Spallart Allmaras turbulence model. A preliminary study on lenticular airship at zero angle of attack shows that sixty six percent of the total drag is comprised of pressure drag. A propeller is introduced to provide axial thrust by aligning it in such a way that it blows fluid parallel to the hull surface, thus energizing the fluid particles, blowing the vortices off the surface and delaying the separation. The objective of the present work is to reduce the pressure drag using propeller. The numerical results shows that blowing of propeller delays the airflow separation and drive the separated vortexes off the body and thus v reduces the drag coefficients. This required a high fidelity CFD modeling approach with appropriate turbulent conditions.