Phasuthorn Phiwphong creator Pennung Warnitchai Chairperson Punchet Thammarak Examination Committee Raktipong Sahamitmongkol Examination Committee Royal Thai Government Fellowship Scholarship Donor text series technical report th Pathum Thani, Thailand Asian Institute of Technology 2020 continuing eng 126 leaves : ill. The main goal of this research is to study the performance of plasma actuators on the aerodynamic force. The circuits which used to drive the plasma actuators were developed at the Nuclear Engineering Department of Chulalongkorn University, which consists of high voltage circuits at a low-frequency range and high voltage circuits at a high-frequency range. The specimen was studied under two basic shapes configuration models which include cylinder and square that the measurement aerodynamic force techniques were included the high-frequency force balance (HFFB) technique and the high-frequency pressure integration (HFPI). This thesis was conducted on free-stream flow conditions at varying wind speeds inside the TU-AIT wind tunnel. From the result of plasma actuators by using high voltage circuits at low-frequency range, for a cylinder model, it was found that the plasma actuators are efficient in reducing the drag force at 1.7 m/s (low wind speed) up to 27%, while the square model can reduce the drag force by 9%. Also, the plasma actuators can effectively streamline in the across-wind flow which can reduce the formation of vortex shedding, as shown by the PSD peak. For cylinder model, the PSD peak is reduced up to 50% at 1.7m/s (low wind speed). at higher wind speed, the plasma actuators are still to reduce the PSD peak by 17-20%. For square model, the PSD peak is reduced up to 27% at 1.7m/s (low wind speed). From the results, the plasma actuators which are driven by high-voltage at low frequency range circuits be effective in the area of low wind speed. The plasma actuators which are driven by high-voltage circuits at the high-frequency range (HF circuit) are better effective in reducing drag force. For cylinder model has the most efficiency at 1.7 m/s (low wind speed) by up to 52%. At higher wind speed, the plasma actuators are also effective which reduces the drag coefficient by 32%, 16% and 13% at wind speed 3.5m/s, 4.9 m/s and 7.1 m/s respectively. For the square model, the plasma actuators did not perform well to reduce the drag force. In addition, the plasma actuators which driven by the HF circuit help to reduce the formation of the Vortex shedding better than the LF circuit. For the cylinder model, the maximum drop is up to 92% at a wind speed of 1.7 m/s. Also, at higher wind speeds, the PSD Peak reduces up to 36-43%. For square model, the peak of PSD reduces by 54% at 1.7m/s (low wind speed). At higher wind speed the plasma actuators are still to reduce the PSD peak by 14-17% From the testing results, the circuit which is driven by high voltage circuit at the high-frequency range (HF circuit) help to control the flow by improving the airflow around the model that works best in reducing the mean drag force. Moreover, it also helps to reduce the formation of Vortex shedding, which causes structural vibrations. A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Structural Engineering, School of Engineering and Technology Thesis (M. Eng.) - Asian Institute of Technology, 2020 Wind tunnels Flow visualization plasma actuators Asian Institute of Technology. http://203.159.5.9/ait-thesis/detail.php?q=B15720 http://203.159.5.9/ait-thesis/detail.php?q=B15720 220210 20260817161457.0