City Research Online

Abstract

Numerical and experimental and investigations have been conducted on a full-scale, high downforce rear wing from a Ferrari Formula One racing car. The wing comprised a main- plane, vane and flap elements incorporating substantial aft camber and for the first time, air jet vortex generators. This study focuses on the wing performance at 19° incidence.

Original numerical investigations were conducted using the CFX-4.2 finite volume, Navier-Stokes, fluid flow solver using non-orthogonal, body-fitted grids. All flows were modelled as steady state, incompressible and fully turbulent using the standard k — e turbulence model for closure of the Navier-Stokes equations.

Two-dimensional numerical studies capture the performance trends of the high down- force wing. When compared with the experiments, the downforce is generally overpredicted by up to 28%. In the three-dimensional numerical studies performed, flow separation is predicted on the suction surface of the mainplane. The application of air jets is predicted to reduce the amount of flow separation through an enhancement of the skin friction above that seen on the model without air jets. An increase in downforce is also predicted for the air jet equipped wing.

Some modifications were made to the wing to facilitate its testing in the City University Low Speed T2 Wind Tunnel at 35 and 40 m/s. These were the installation of the air jets, static pressure orifices, and the fitting of endplates. Boundary-layer control was not applied to the endplates.

In the experiments, at high angles of incidence, the wing experiences incipient flow separation on the suction surface of the mainplane. The application of air jets reduces this flow separation and also increases the downforce generated by the wing over that of the wing without air jets.

The interactions of the experimental and numerical solutions reveal the mechanisms by which the air jets enable the wing to generate more downforce. Nevertheless, additional work is needed to address issues such as the degree of two dimensionality of the flow fields in the experiments and grid sensitivity of the numerical results.

Publication Type:	Thesis (Doctoral)
Subjects:	T Technology > TJ Mechanical engineering and machinery
Departments:	School of Science & Technology > Mathematics School of Science & Technology > School of Science & Technology Doctoral Theses Doctoral Theses

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