Effect of nozzle depth to acoustic signals produced by a Ranque-Hilsch Vortex Tube / Wirachman Wisnoe and Khairil Muhaimin Abd Rahman

This paper aims to present the analysis of acoustic sound produced from a Ranque-Hilsch Vortex Tube. Two microphones are used to capture the sound produced at the hot and cold tubes. Different nozzle depths of the swirl generator are tested and different inlet pressure gages are applied. It is observed that, for one swirl generator, the sound produced contains a specific set of frequencies. These frequencies remain present when the inlet pressure is varied, while the magnitude of these frequencies changes. Different swirl generator produces different set of frequencies. These sets of frequencies-magnitudes represent acoustic signatures of the configurations. This acoustic signature is then linked with their thermofluid performance

Design parameters for the development of wing test rig for static test experiment / Ramzyzan Ramly … [et_al.]

Airplanes are designed to stay aloft with the help of wings on both sides. In operation at cruising speed, the wings are subjected to load as much as the weight of the whole aircraft. However during manuever, the wings are subjected much higher load and stress and this stress should be sustained by the wings within its limit load without causing permanent deformation to the strucutre. In order to assess how much stress the wings are subjected to, the wings should be tested on ground which is called static test. To proof that a design is good, a numerical analysis should be verified by experimental analysis. The static test can be done in a test rig. The test rig however should be much stronger than the object to be tested. Therefore, the design parameters such as materials selection, design configuration, mounting types, points of load application, boundary conditions are among the parameters to be studied in the development of the test rig. From the research, the simulation was done using CATIA software and the numerical tests was done using ANSYS software. The results from the simulation provided a good picture of the test rig and a prototype was developed using a 40% scale af the actual size being studied

The Effect of Elevons Deflection to Aerodynamic Coefficients of A Tail-less Blended Wing-Body Planform / Rizal E. M. Nasir ...[et al.]

Control surfaces play a big role in stabilizing and maneuvering an aircraft. This paper investigates the effect of control surface allocations, specifically deflection of four elevons on a BWB planform, on aerodynamic coefficients. Elevon allocations can be in a form of single-elevon deflection, two-elevon deflection in unison or in opposite deflection angles and four-elevon deflections in unison or in opposite deflection angles. Six aerodynamic coefficients which represent three forces and three moments in three axes are measured via wind tunnel experiment at 25 m/s. The wind tunnel model is of a flat, thin plate with planform similar to a typical stealth, flying-wing aircraft. Thirty-one (31) cases of different elevon deflections are tested at a fixed pitch angle of attack and zero angle of sideslip. The results shows that significant changes in drag, sideforce and lift forces are observed at almost all elevon deflection cases. The roll moment and pitch moment change with respect to elevon angle depends on the number of elevons utilized while yaw moment is not much affected by elevon deflections except for some cases

Wind Tunnel Tests of UiTM Blended Wing Body - Unmanned Aerial Vehicle (BWB-UAV) Prototype / Wirachman Wisnoe ...[et al.]

In 2014 Universiti Teknologi MARA (UiTM) Malaysia has been granted a research project under Prototype Research Grant Scheme from the Ministry of Higher Education Malaysia to build a prototype of Blended Wing Body - Unmanned Aerial Vehicle for aerial surveillance. In this paper the aerodynamic characteristics of the prototype in the longitudinal direction are presented in terms of lift coefficient, drag coefficient, and pitching moment coefficient obtained from wind tunnel tests. The tests are conducted on a ¼ scaled half model aircraft placed in UiTM Low Speed Tunnel at wind speed of 20 m/s, 25 m/s, 30 m/s, 35 m/s and 40 m/s representing Reynolds number in the order of 105. For each wind speed, the angle of attack is varied from -10º to 64º to observe the full capability of the aircraft. Visualisation using thread tufts is also executed to see the flow pattern on the surface of the aircraft at certain angles. The results show that the maximum lift coefficient is around 0.65 at 28º angle of attack, the minimum drag coefficient is below 0.03 at zero angle of attack, and the maximum lift-to-drag ratio is about 20 at 3º angle of attack. The pitching moment curve indicates a static stability with negative slope between -7º to 10º angle of attack. Visualisation shows the flow separation progress on the surface of canard, wing and fuselage

An evaluation of cots-based radar for very small drone sense and avoid application

The use of very small unmanned aerial vehicles (UAVs) are increasingly common these days but its applications are limited to the pilot line-of-sight view. To extend its use beyond the pilot view, UAVs need to be equipped sense and avoid (SAA) system to avoid potential collisions. However, the development of SAA for very small drones is still in the infancy stage mainly due to the high cost of design and development for reliable range sensors. Recent developments of very small size and lightweight commercial off-the-shelf (COTS)-based radar systems may become a crucial element in very small drone applications. These types of radars are primarily developed for industrial sensing but can be adapted for applications such SAA. Thus, this paper contributes to the survey of a miniature and lightweight radar sensor to assist the SAA development. The focus of this paper is to analyse the eligibility of a COTS-based radar in detecting very small drones. For this purpose, we used a frequency-modulated continuous radar (FMCW) developed by Infineon Technologies. Field test results show the real-time capability of the radar sensor to detect the very small drones within ± 0.5 meters in static and dynamic conditions

Aerodynamics prediction of multi-purpose UAV using wind tunnel experimental approach / Ghazirah Mustapha @ Mustafa, Zurriati Mohd Ali, Wirachman Wisnoe

Aerodynamics is a branch of dynamics concerned with the study of fluid flow and the interaction of the atmosphere around the objects. The calculation of important performance indicator such as forces and moments acting on an object can be made with the deep understanding of the motion of air around an object. In aviation, aerodynamic is one of the most important fields to consider when designing a new or modifying the existing airplane. The collections of aerodynamic database, for example lift, drag and moments force will help the designers and aeronautical engineers to improve the aerodynamic design and the performance of the airplane. Since the first airplane has been developed, the design and performance of the airplane is getting better. Many years of studies in aerodynamics leads people to find a way and solutions on how to makes airplane or any flying object to get the maximum capability in speed, performance, ability in any maneuvering and prediction of forces and moment. Aerodynamics investigation and analysis can be classified according to the ratio of the problem’s characteristics flow speed to the speed of sound. Subsonic is a second classification of aerodynamics which all the speed in the problem are less than the speed of sound. At present, the design of unmanned aircraft vehicle,UAV is one of the most challenging tasks in aerodynamic studies. In UAV design, the placement of the wing, tail and canard is somehow, not the same as in the conventional airplane configuration. There are a lot of UAV designs such as peanut shape (Canadair CL-227 Sentinel), VTOL UAV with counter-rotating blades and variation of shapes in the planform wings and tails. These configurations need a lot of aerodynamic skills and knowledge to ensure that the UAVs can safely take off, loiter and land

The Effect of Orifice Diameter to the Acoustic Signals Captured at the Cold Part of a Ranque-Hilsch Vortex Tube

In this study, acoustic analysis and thermofluid performance of a Ranque-Hilsch Vortex Tube (RHVT) is experimentally investigated under different orifice diameters at its cold tube. The orifice diameters used are 2mm, 3 mm, 4 mm, 5 mm and 6 mm. The inlet pressure (gage) is set at 10 psi, 15 psi, 20 psi and 25 psi for each orifice diameter. The sound produced by the tube is recorded using a microphone located outside the cold tube. The acoustic signal is processed using Fast-Fourier Transform (FFT) to obtain the frequency representation. Main frequencies are then extracted to constitute the signature of the signal for that specific configuration. It is observed that different orifice diameters give different signatures. These signatures are then associated with the thermofluid performance of the device to obtain the relation among the parameters

Computational aerodynamic analysis of UiTM's Hawkeye UAV aircraft

This paper discusses the aerodynamic characteristics of Hawkeye UAV aircraft with a forward-swept wing configuration. The unconventional wing design on Hawkeye allows for better maneuverability and stability during a field test but there were no prior studies on its aerodynamic characteristics. A series of CFD simulations were conducted using ANSYS Fluent to obtain the aerodynamic characteristic of Hawkeye; lift, drag and moment coefficient. A full-size model and Reynolds-averaged Navier-Stokes (RANS) numerical method-based equations, Spalart-Allmaras turbulence model was used for the simulation. The angle of attack of the aircraft differs from -10° to 30° with an interval of 2° at a flight condition of Mach number 0.1 (~35 m/s). The CFD results obtained will be used to calculate the aircraft performance in a real field test and for future improvement of the UAV

Aerodynamic Analysis of Blended Wing Body - Unmanned Aerial Vehicle (BWB-UAV) Equipped with Horizontal Stabilizers

This paper presents an aerodynamic characteristic study in longitudinal direction of UiTM Blended Wing Body-Unmanned Aerial Vehicle Prototype (BWB-UAV Prototype) equipped with horizontal stabilizers. Flight tests have been conducted and as the result, BWB experienced overturning condition at certain angle of attack. Horizontal stabilizer was added at different location and size to overcome the issue during the flight test. Therefore, Computational Fluid Dynamics (CFD) analysis is performed at different configuration of horizontal stabilizer using Spalart - Allmaras as a turbulence model. CFD simulation of the aircraft is conducted at Mach number 0.06 or v = 20 m/s at various angle of attack, α. The data of lift coefficient (CL), drag coefficient (CD), and pitching moment coefficient (CM) is obtained from the simulations. The data is represented in curves against angle of attack to measure the performance of BWB prototype with horizontal stabilizer. From the simulation, configuration with far distance and large horizontal stabilizer gives steeper negative pitching moment slope indicating better static stability of the aircraft

Aerodynamic Analysis of Blended Wing Body - Unmanned Aerial Vehicle (BWB-UAV) Equipped with Horizontal Stabilizers

This paper presents an aerodynamic characteristic study in longitudinal direction of UiTM Blended Wing Body-Unmanned Aerial Vehicle Prototype (BWB-UAV Prototype) equipped with horizontal stabilizers. Flight tests have been conducted and as the result, BWB experienced overturning condition at certain angle of attack. Horizontal stabilizer was added at different location and size to overcome the issue during the flight test. Therefore, Computational Fluid Dynamics (CFD) analysis is performed at different configuration of horizontal stabilizer using Spalart - Allmaras as a turbulence model. CFD simulation of the aircraft is conducted at Mach number 0.06 or v = 20 m/s at various angle of attack, α. The data of lift coefficient (CL), drag coefficient (CD), and pitching moment coefficient (CM) is obtained from the simulations. The data is represented in curves against angle of attack to measure the performance of BWB prototype with horizontal stabilizer. From the simulation, configuration with far distance and large horizontal stabilizer gives steeper negative pitching moment slope indicating better static stability of the aircraft