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Recent research into the phenomenon of tire hydroplaning has concentrated on the effects of possible path clearing of the rear tires by the front tires. When this occurs, the rear tire behavior and hydroplaning properties will be different from what would occur had the tire been running in an undisturbed flow field. In the present work, we modify rear tire properties to simulate the path clearing effect and utilize the SIMON/HVE suite of simulation programs with a standardized double lane change maneuver to examine path clearing potential during transient vehicle behavior.

A. brief survey of vehicle dynamics and aerodynamics papers pertinent to open wheeled racing cars is presented. In this work, the aerodynamics of Indy cars have been studied from both a lift and drag point of view. A standardized definition of lifting area for ground effects vehicles and performance observations made through the use of radar and track simulations were used. Values for negative lift magnitude were determined, lifting area was photogrammetrically measured, and a lift coefficient appropriate for Indy cars was developed. Drag area, also obtained photogrammetrically, and drag coefficients were developed. Mechanical measurements of vehicles and wind tunnel experiments were used to estimate total drag and subsequent values for drag coefficients. These values correspond with energy balance calculations based on available engine power. A sensitivity study of the performance parameters of Indy cars was performed, with emphasis on enhancing top speed.

Traditional vehicle simulations use two methods of modeling driver inputs, such as steering and braking. These methods are broadly categorized as “Open Loop” and “Closed Loop”. Open loop methods are most common and use tables of driver inputs vs time. Closed loop methods employ a mathematical model of the driving task and some method of defining an attempted path for the vehicle to follow. Closed loop methods have a significant advantage over open loop methods in that they do not require a trial-and-error approach normally required by open loop methods to achieve the desired vehicle path. As a result, closed loop methods may result in significant time savings and associated user productivity. Historically, however, closed loop methods have had two drawbacks: First, they require user inputs that are non-intuitive and difficult to determine. Second, closed loop methods often have stability problems.

Recent research on the effects of tire hydroplaning has examined the hydroplaning phenomenon and its potential effects on vehicle maneuvering from (1) geometric, (2) straight line braking/acceleration and (3) steady-state cornering maneuver points of view. In this work, we focus on the potential for hydroplaning during a transient maneuver: a standardized double lane change maneuver (ISO3888-1). Using both closed-form calculations and the HVE software suite, it is shown that partial hydroplaning has only a small-to- moderate potential to occur during portions of such maneuvers, but is not likely throughout the entire duration of the maneuver.