Computational tools have led and helped researchers in providing advanced results, notably in rotorcraft research, as flow around the helicopter is dominated by complex aerodynamics and flow interaction phenomena. This research work aimed to evaluate the aerodynamic computational results on a simplified model helicopter when the model was subjected to the angles of attack 0°, -5°, -15°, and -20°, respectively. The study also examined the unsteady flow behaviour on the three-dimensional elliptical shape of a fuselage equipped with a rotor hub of the single rotor blade. The computational domain for the aerodynamic flow field was created within the size of 7 m (length) x 5 m (width) x 5 m (height). Results showed that an increase in the angle of attack in the rotor component caused additional drag of about 34% to 45% whilst the fuselage component contributed about 55% to 65% to drag increment. Also, a significant value of total pressure from -235 Pa to 250 Pa demonstrated along the simplified model helicopter distinctly showed that the complexity of geometry caused adverse pressure. The findings of this research work could potentially improve the understanding of complex flow surrounding the helicopter that has always baffled the aerodynamicists.

Diffusing S-shaped ducts are critical components in modern vehicle, primarily employed in directing the airflow to the engine. It links the air box and the engine in a very restricted place. The air flow through an S-duct is complex in nature, which perhaps includes boundary layer separation, secondary flow, and total pressure loss effects that influences the engine performance. In this work, the flow and performance of S-shaped duct was predicted and analysed using computational fluid dynamics. The main objective is to evaluate the performance of the realizable k-ε and k-ω SST models qualitatively and quantitatively in modelling flow of a highly bend duct where a high stress distorted flow may have developed in proximity the duct wall leading to stall. CFD computations were performed for the flow entering the diffuser at Reynolds number of 80,000 cases. The results obtained suggested that the k-ω SST model reasonably predicts the flow characteristics qualitatively and quantitatively. The realizable k-ε turbulence model however poorly captures the actual magnitudes of the calculated flow features. The growth of the stream-wise velocity profile was calculated at three stream-wise stations and point out a smooth down the interior profile of the divergent section. An extreme flow distortion and a shift of the region of flow with the highest velocity were developed toward the outer wall of the first bend of the diffuser. A significant pressure recovery potential with no flow separation arise over the diffuser tube range was predicted well by the simulations.

Induction system or also known as the breathing system is a sub-component of the internal combustion system that supplies clean air for the combustion process. A good design of the induction system would be able to supply the air with adequate pressure, temperature and density for the combustion process to optimizing the engine performance. The induction system has an internal flow problem with a geometry that has rapid expansion or diverging and converging sections that may lead to sudden acceleration and deceleration of flow, flow separation and cause excessive turbulent fluctuation in the system. The aerodynamic performance of these induction systems influences the pressure drop effect and thus the engine performance. Therefore, in this work, the aerodynamics of motorcycle induction systems is to be investigated for a range of Cubic Feet per Minute (CFM). A three-dimensional simulation of the flow inside a generic 4-stroke motorcycle airbox were done using Reynolds-Averaged Navier Stokes (RANS) Computational Fluid Dynamics (CFD) solver in ANSYS Fluent version 11. The simulation results are validated by an experimental study performed using a flow bench. The study shows that the difference of the validation is 1.54% in average at the total pressure outlet. A potential improvement to the system have been observed and can be done to suit motorsports applications.

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This paper presents the performance of a piezoelectric Synthetic Jet Actuator (SJA) in quiescent flow. Pulse jet velocity and vorticity were taken as the parameter to evaluate the performance of SJA. PIV measurements on the jet flow at the orifice exit of a round SJA were conducted by varying the oscillating in frequency and voltage. The location of 5mm above orifice was identified as the optimum location for maximum pulse jet measurements. The maximum pulse jet velocity and vorticity obtained were 18.77 m/s and 242.5s-1. The PIV experiment showed that by varying oscillating frequency at fixed input voltage, the performance of  SJA was greatly affected by Helmholtz resonance. While in the investigation of varying input voltage at fixed oscillating frequency, diaphragm defection was the parameter that affects the performance of the SJA. Besides, PIV measurement showed that the flow patterns of vortex structure formation were affected by the oscillating frequency and pulse jet velocity.