Date Approved

12-2017

Graduate Degree Type

Thesis

Degree Name

Engineering (M.S.E.)

Degree Program

School of Engineering

First Advisor

Dr. Wael Mokhtar

Second Advisor

Dr. Mehmet Sozen

Third Advisor

Dr. Sung-Hwan Joo

Academic Year

2017/2018

Abstract

Presently, one of the key factors in determining a success of an open wheel racecar such as Formula One or Indy car, is its aerodynamic efficiency. A modern racecar front wing can generate about 30% of the total downforce. The present study focuses on investigating the aerodynamic characteristics of such highly efficient multi-element front wing for a Formula One racecar by conducting a three-dimensional computational analysis using Reynolds Averaged Navier-Strokes model. A three-dimensional computational study is performed investigating predictive capability of the structured trimmer and unstructured polyhedral meshing model to generate a three-dimensional volume mesh for a multi-element front wing. Also, the ability of the standard k- ω Shear Stress Transport (SST) and the one equation Spalart-Allmarus turbulence models to predict the three-dimensional flow over a multi-element front wing operating in ground effect has been investigated. Furthermore, the present study also determines the effect of varying ground clearance and angle of attack. Lastly, the aerodynamic characteristics of the wing operating in the wake of racecar in front is also investigated with the help of a generic bluff body. To get more realistic results a moving ground simulation has been used. It has been observed that the RANS model is able to predict the three-dimensional flow over the double element front wing correctly. Both of the turbulence models are able to predict the flow over the front wing in decreasing ground clearance and indicate the regions of force enhancement and force reduction. However, for low ground clearances, the standard k- ω SST turbulence model is best suited as it is able to predict the flow more accurately. Moreover, the results indicate, use of unstructured polyhedral mesh model for meshing of wing is more effective. By studying the flow characteristics of the wing at different ground clearances, it has been observed that the downforce generated behaves as a function of ground clearance. Furthermore, by studying the lift and drag forces generated by the wing, it has also been observed that the wing clearly operates in three different regions which can be classified as; a region similar to free stream case, a force enhancement region and a force reduction region. In addition, by investigating the effect of increasing angle of attack for forces generated, the study indicated that for lower values of angle of attack the corresponding very low ground clearances has more impact in decreasing the downforce generated. However, for higher angle of attack, the resulting increase in camber has a significant impact than very low ride heights which leads to an increase in downforce generated. Moreover, the studies for front wing operating in wake show the downstream wing is significantly affected by the up-wash flow field from the leading racecar leading to a loss of downforce. However, the leading racecar also creates a drafting effect which can be used to get as a tow and improve straight-line speeds of following racecar.

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