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A KIA Soul was instrumented to measure the relative velocity (magnitude and yaw angle) at the front of the vehicle and in-cabin sound at a location close to the side glass near the A-pillar vortex impingement. Tests were conducted at a proving ground under a range of conditions from low wind conditions (~3 m/s) to moderate (7-8 m/s) wind speeds. For any given set of atmospheric conditions the velocity and sound data at any given position on the proving ground were noted to be very repeatable, indicating that the local wakes dominated the "turbulent" velocity field. Testing was also conducted in an aeroacoustic wind tunnel in smooth flow and with a number of novel turbulence generating methods. The resulting sounds were analyzed to study the modulation at frequencies likely to result in fluctuation strength type noise.

Wind tunnels provide a convenient, repeatable method of assessing vehicle engine cooling, yet important draw-backs are the lack of a moving ground and rotating wheels, blockage constraints and, in some tunnels, the inability to simulate ambient temperatures. A series of on-road and wind-tunnel experiments has been conducted to validate a process for evaluating vehicle cooling system performance in a high blockage aerodynamic wind tunnel with a fixed ground simulation. Airflow through the vehicle front air intake was measured via a series of pressure taps and the wind-tunnel velocity was adjusted to match the corresponding pressures found during the road tests. In order to cope with the inability to simulate ambient temperatures, the technique of Specific Dissipation (SD) was used (which has previously been shown to overcome this problem).

Effective rear view vision from external mirrors is compromised at high speed due to rotational vibration of the mirror glass. Possible causes of the mirror vibration are reviewed, including road inputs from the vehicle body and a variety of aerodynamic inputs. The latter included vibrations of the entire vehicle body, vibrations of the mirror “shell”, the turbulent flow field due to the A-pillar vortex (and to a lesser extent the approach flow) and base pressure fluctuations. Experiments are described that attempt to understand the relative influence of the causes of vibration, including road and tunnel tests with mirrors instrumented with micro accelerometers. At low frequencies, road inputs predominate, but some occur at such low frequencies that the human eye can track the moving image. At frequencies above about 20Hz the results indicate that at high speeds aerodynamics play a dominant role.

Green racing technologies are described with a focus on two categories of sustainable racing; solar racing, including an overview of the World Solar Challenge (WSC) held in Australia, and Formula SAE-E (Society of Automotive Engineers-Electric). Both types of cars utilise sustainably generated electricity, the former uses solar arrays integrated into the vehicle body and the latter electricity generated from a renewable energy park and stored onboard in lithium polymer cells. The design considerations of both vehicles are contrasted with a focus on energy usage minimisation. The Aurora team (which has broken many records, including winning the World Solar Challenge across Australia) is used to illustrate the importance of minimizing the power requirements by having a low aerodynamic drag, frontal area, a highly efficient powertrain and low rolling resistance. To illustrate the technology behind FSAE Electric the R10E car from RMIT is described.

Separated flow is the main generator of aerodynamic noise in passenger vehicles. The flow around the A-pillar is central to the wind noise as many modern vehicles still have high fluctuating pressures due to flow separations in this region. Current production vehicle geometry is restricted due to the amount of three dimensionality possible in laminated windscreen glass (and door opening etc). New materials (e.g., polycarbonate) offer the possibility of more streamlined shapes which allow less or no flow separation. Therefore, a series of experimental investigations have been conducted to study the effects of the A-pillar and windshield geometry and yaw angles on the local flow and noise using a group of idealised road vehicle models. Surface mean and fluctuating pressures were measured on the side window in the A-pillar regions of all models at different Reynolds numbers and yaw angles.

For high-speed driving conditions, the air flow around a car creates wind noise that is transmitted into the cabin, which can dominate other noises. If an atmospheric wind is present, it will create a turbulent cross wind, which not only changes the air flow velocity and direction as experienced by the vehicle, but leads to continuously varying wind noise, as heard inside the car. The purpose of this paper is to look at how the on-road wind environment affects wind noise, and to evaluate the need to simulate real on-road conditions such as fluctuating yaw angles and velocities in vehicle wind tunnels.

The sensitivity of cross-winds in reducing the engine cooling ability in motor cars is highlighted. Tests on three different motor cars were conducted in the Monash University full-scale wind tunnel at different yaw angles under different wind velocities. The test results show that motor car engine cooling capability decreases with an increase in yaw angles. For a wind velocity of 14 m/s, a 13% decrease in radiator cooling capability was found at a yaw angle of 20° compared to a zero yaw angle. The effect of yaw angles on the engine cooling also depends on the motor car front-end configuration, but this becomes less important with increasing wind velocity. The effect of cross-winds on car engine cooling was also evaluated by on-road engine cooling tests. A convenient experimental method to measure wind velocity and yaw angle relative to a moving car is also described.

The design of the exterior body shape and structure of a solar-electric sports car which competed in the 2019 Bridgestone World Solar Challenge (BWSC) Cruiser Class is explored. A low-drag and low-lift aerodynamic shape with a coefficient of lift near zero and drag area of 0.16 m2 is developed as a primary focus around the constraints of a solar array, occupant space, and aesthetics. The maximally sized 5 m2 rearward tilted solar array capable of generating an expected event average power of 885 W influences the size and shape of the roof. The space for which two occupants are seated in the vehicle is developed to achieve a reclined occupant position that minimizes the vehicle frontal area. A carbon fiber-reinforced polymer (CFRP) and foam composite sandwich monocoque make up the structure of the vehicle at a mass of 59.53 kg. Factors of practicality and their compromises are also explored.

A morphing ram-air intake, capable of deploying from a flat, closed surface to an open state is investigated. Via geometric and material optimisation, an origami-inspired folding structure is developed to exhibit bi-stable behaviour. An iterative finite element design process was conducted, noting the effects of the critical design properties of geometry, bending stiffness and material strain limits on bi-stability and the achievable geometric shape change. As a first step, thermoplastic polyurethane elastomer materials are proposed while increased stiffness by fibre reinforcements are considered at a later design stage and evaluated under aerodynamic loading. The bi-stable structure is capable of remaining in either open or closed stable configurations without sustained actuation. The ability to retract the intake when not required has the potential to reduce drag. It is envisioned that such a concept may be readily adopted within automotive and aerospace applications.

Smart material is a suitable candidate for adaptive airfoil design as it can be customized to generate a specific response to a combination of inputs. Shape memory alloy (SMA) in particular is lightweight, produces high force and large deflection which makes it a suitable candidate for actuator in the adaptive airfoil design. By attaching SMA wires inside the airfoil, they can be activated to alter the shape of the airfoil. Placement of the actuator is crucial in obtaining the desired change of the airfoil camber. This paper proposed a design for the morphing wing aimed at changing the camber of the airfoil during cruise in order to increase the lift-to-drag ratio. Finite Element Method (FEM) analysis predicted the deformed airfoil geometry when the SMA wires were fully actuated. Numerical results are presented along with issues related to the fabrication of the morphing wing and implementation of the SMA actuator.

The paper presents experimental analysis of the airflow around the differential center housing of a rear drive full-scale passenger car. The study included investigation of local airflow total and static pressure, as well as surface flow visualization. Estimation of the local airflow velocity is based on the measured pressure coefficients. The experiments were carried out at different test facilities: in a climatic wind tunnel, in a full-scale wind tunnel and on-road. Influence of side wind was modeled by the yawing of the car in the full-scale wind tunnel. The results show the asymmetrical structure of the flow in both, vertical and horizontal planes. Estimated longitudinal relative local velocity decreases from maximum Vr ≈ 0.4 at the lower surface of the center housing, to about Vr ≈ 0 above the upper surface. Side wind increases airflow velocity around the center housing within the investigated yaw range ± 20°