Ingenieur Vol 80 ingenieur 2019 octoberfinal | Page 34

INGENIEUR design (CAD) software design and dimensions. The prototype is manufactured using a CNC hot wire cutter machine. Then, the reinforcement of the wing structure fibre is implemented through the fiberglass lay-up process using advanced composite techniques. This platform is built for a wide range of usage in the industry. It can be used by researchers as their research platform, land surveyors for aerial mapping missions, Government agencies such as the police for aerial patrolling, and drone companies for their drone fleet. The unique selling proposition of this project is its functionality, which only uses one platform for multiple configurations in different types of environment or usage. It is also unique for its low manufacturing cost compared to commercial UAVs in the market. Figure 4: Members of My Drone Tech project #4. Aeroacoustic Investigation on the effect of Leading Edge serrations on Airfoil by Universiti Teknologi Malaysia Airfoils are an important component in many engineering applications. However, the airfoil is also responsible in the emission of airfoil self- noise. The airfoil self-noise generation can be classified into sound at the leading edge (LE) and sound at the trailing edge (TE). When the turbulent 6 32 VOL 2019 VOL 80 55 OCTOBER-DECEMBER JUNE 2013 Flow trace at the serrations in the Leading Edge of the airfoil eddies from the upstream interact with the LE of the airfoil, the airfoil-turbulence interaction noise (ATIN) is produced. ATIN is the focus of this study as it is present in many cases including the wind turbines, rotors and turbofan engines. The LE serrations are one of the treatments to reduce ATIN. The stiff comb-like structures at the LE of their wings are one of the unique features that enable the barn owl’s silent flight. LE serration is a passive control method that is bio-inspired from humpback whale flippers and from the barn owl’s silent flight. To date, many positive findings show that LE serrations are also able to enhance hydro and aerodynamic performance at post-stall conditions. As for the hydro and aerodynamic point of view, many studies have highlighted that stall can be delayed by the introduction of serrations at the leading edge. Until recently, most studies have been investigating the effectiveness of particular parameters of the LE serrations on the ATIN reduction mechanism. By taking the rod-airfoil as the benchmark configuration of ATIN generation mechanisms, the current study aims to inspect the effect of placing vortex generators to the serrations on the ATIN. The airfoil model being used is NACA 0012 and the rod (with diameter D) is placed 3.5D upstream of the airfoil in order for the airfoil to experience complete turbulence inflow. Flow calculations are carried out three- dimensionally by employing Delayed Detached Eddy Simulation (DDES), while the aerodynamic noise calculation is solved by using the Ffowcs Williams-Hawkings (FW-H) equation. The sound results are validated with the experimental results of the rod-airfoil baseline case. This study expects