Tholudin Mat Lazim

Development of delta wing aerodynamics research in Universiti Teknologi Malaysia low speed wind tunnel

This paper presents wind tunnel experiment on two delta wing configurations which are differentiated by their leading edge profiles: sharp and round-edged wings. The experiments were performed as a part of the delta wing aerodynamics research development in Universiti Teknologi Malaysia, low speed tunnel (UTM-LST). Steady load balance and flow visualization tests were conducted at Reynolds numbers of 0.5, 1, and 1.5 × 106, respectively. The flow measurement at low Reynolds number was also performed at as low as speed of 5 m/s. During the experiments, laser with smoke flow visualizations test was performed on both wings. The study has identified interesting features of the interrelationship between the conventional leading edge primary vortex and the occurrence and development of the vortex breakdown above the delta wings. The results conclude the vortex characteristics are largely dependent on the Reynolds number, angle of attack, and leading-edge radii of the wing.

Computational Fluid Dynamic Simulation (CFD) and Experimental Study on Wing-external Store Aerodynamic Interference of a Subsonic Fighter Aircraft

The main objective of the present work is to study the effect of an external store on a subsonic fighter aircraft. Generally most modern fighter aircrafts are designed with an external store installation. In this study, a subsonic fighter aircraft model has been manufactured using a computer numerical control machine for the purpose of studying the effect of the aerodynamic interference of the external store on the flow around the aircraft wing. A computational fluid dynamic (CFD) simulation was also carried out on the same configuration. Both the CFD and the wind tunnel testing were carried out at a Reynolds number 1.86×10 5 to ensure that the aerodynamic characteristic can certify that the aircraft will not be face any difficulties in its stability and controllability. Both the experiments and the simulation were carried out at the same Reynolds number in order to verify each other. In the CFD simulation, a commercial CFD code was used to simulate the interference and aerodynamic characteristics of the model. Subsequently, the model together with an external store was tested in a low speed wind tunnel with a test section sized 0.45 m×0.45 m. Measured and computed results for the two-dimensional pressure distribution were satisfactorily comparable. There is only a 19% deviation between pressure distribution measured in wind tunnel testing and the result predicted by the CFD. The result shows that the effect of the external storage is only significant on the lower surface of the wing and almost negligible on the upper surface of the wing. Aerodynamic interference due to the external store was most evident on the lower surface of the wing and almost negligible on the upper surface at a low angle of attack. In addition, the area of influence on the wing surface by the store interference increased as the airspeed increased.

Reynolds number effects on flow topology above blunt-edge delta wing VFE-2 configurations

This paper discusses further the effects of Reynolds number, angle of attack and leading edge bluntness on the flow topology above delta wing VFE-2 configurations. In this project two delta wing models differentiated by its leading edge radius to the mean aerodynamics chord ratio of 0.15 and 0.3, namely the medium and large radius wing, were tested in Universiti Teknologi Malaysia wind tunnel. The relationship between the leading edge primary vortex and the occurrence of a secondary vortex called the inner vortex on the round-edged delta wings are discussed. The effects of leading edge bluntness, angle of attack and Reynolds number on both vortex systems are further discussed in this paper. The tests in this study were performed at speeds of 18.0 m/s, 36.1 m/s, and 54.2 m/s representing Reynolds numbers of 1×106, 2×106 and 3×106 and based on the mean aerodynamic chord. Two measurement techniques were employed on the models i.e. steady force balance and surface pressure data. The current experiments showed that an increase in leading edge bluntness and Reynolds number can delay the formation of the primary vortex towards the aft portions of the wing.

Aerodynamic Analysis of the Preliminary Design of SURIAKAR 4 Using CFD

A four-wheel solar car, the SURIAKAR 4, was designed based on the revised regulations of the Challenger Class World Solar Challenge (2013). It is a four-wheel car with the front and back wheels enclosed in a wind cheating cover. The cockpit is located in such a way that it sits between the front and rear wheel, within the wheel cover on the right side of the car. This paper investigates the aerodynamic characteristics of the car, especially the drag and lift forces, and other forces and moments that determine the stability of the car using CFD package ANSYS Fluent. The model analysis was done with 2.23 million elements after a thorough grid independence study was conducted. The drag coefficient of SURIAKAR 4 is 0.1817. With a frontal area of 0.8934 m2 and at the design speed, the car requires 2132 W of power to overcome this aerodynamic drag. The results also showed that the airflow quality around the car is relatively well-behaved, with only a few turbulent flow points identified. This flow incurs drag penalty and thus have to be modified.

Mathematical Modelling of Droplet Atomization Using the Population Balance Equation

This study investigates numerically the atomization process occurring in a plain jet airblast atomizer. The population balance equation is solved for the dispersed phase coupled with a CFD Eulerian multi-fluid model. The Sauter mean diameter values obtained numerically compare favorably with previous experimental data only at certain flow conditions. Finally, this study proposes some enhancements on using the numerical model which were revealed from the model formulation and the results obtained.

Computational Fluid Dynamic Simulation (CFD) and Experimental Study on Wing-external Store Aerodynamic Interference

The main objective of the present work is to study the effect of an external store to a subsonic fighter aircraft. Generally most modern fighter aircraft is designed with an external store installation. In this project a subsonic fighter aircraft model has been manufactured using a computer numerical control machine for the purpose of studying the effect of the external store aerodynamic interference on the flow around the aircraft wing. A computational fluid dynamic (CFD) and wind tunnel testing experiments have been carried out to ensure the aerodynamic characteristic of the model then certified the aircraft will not facing any difficulties in stability and controllability. In the CFD experiment, commercial CFD code is used to simulate the interference and aerodynamic characteristics of the model. Subsequently, the model together with an external store was tested in a low speed wind tunnel with test section sized 0.45 m×0.45 m. Result in the two-dimensional pressure distribution obtained by both experiments are comparable. There is only 12% deviation in pressure distribution found in wind tunnel testing compared to the result predicted by the CFD. The result shows that the effect of the external storage is only significant at the lower surface of the wing and almost negligible at the upper surface of the wing. Aerodynamic interference is due to the external storage were mostly evidence on a lower surface of the wing and almost negligible on the upper surface at low angle of attack. In addition, the area of influence on the wing surface by store interference increased as the airspeed increase.