Shabudin Mat

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.

The effect of edge profile on delta wing flow

This paper presents flow measurements on four delta wing configurations which are differentiated by their leading edge profiles; sharp-edged, small, medium, and large radius. The experiments were performed as a part of the European Vortex Flow Experiment-2 campaign. Tests were conducted at speeds of 20.63 m/s and 41.23 m/s representing Reynolds numbers of 1 × 106 and 2 × 106, respectively. In this paper, oil flow visualization data are presented for the four wings together with particle image velocimetry results for the large radius wing. The study has identified interesting features of the interrelationship between the conventional leading edge primary vortex and the occurrence and development of the inner vortex on the round-edged delta wings. The effects of Reynolds number, angle of attack, and leading-edge radii on both vortex systems are discussed in detail.

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.

Manufacturing Process of Blended Delta-Shaped Wing Model

Aerodynamicists have long acknowledged the blended wing body (BWB) aircraft design could produce great aerodynamic advantages due to the integration of the delta wing structure with the thick center body. Therefore the wind tunnel test campaign is crucial to gain information of the flow field that governs the delta-shaped wing which has frequently baffled the aerodynamicists. In such, the wind tunnel test required acceptable quality of delta-shaped wing model for results validity. Consequently, the manufacturing process as well as the selection of the appropriate machinery tools, must be wisely designed and performed. The modular 3D concept in associating with CAD/CAM technology was utilised in the process. Finally, the actual flow cycle of manufactures blended BWB aircraft model was sucessfully established. The objective of this paper is to highlight those complexity manufacturing process and techniques involved in order to produce a good blended delta-shaped wind tunnel model.

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.