A NUMERICAL STUDY ON THE IMPACT OF SPOILER ORIENTATION AND GEOMETRY ON SALOON CAR AERODYNAMICS

Abstract

According to data from the Ministry of Energy and Mineral Resources (ESDM), energy consumption in Indonesia has exhibited a consistent upward trend. In 2023, it increased by 6.29% compared to the previous year.  The transportation sector accounted for 37% of total energy consumption in 2023, which is considered very high. Therefore, it is essential to improve energy efficiency in this sector. One effective way to achieve this is by using vehicle designs that are more energy-efficient, particularly those with aerodynamic shapes. Vehicles with lower drag force can reduce fuel consumption significantly. Several studies have proposed the integration of external aerodynamic devices—such as vortex generators, rear spoilers, rear fairings, and fenders—aimed at actively manipulating airflow around the vehicle to reduce aerodynamic resistance The objective of this study is to investigate the effect of spoilers on the aerodynamic performance of a car. The research employs a numerical method using ANSYS Fluent software to analyze the resulting drag force, pressure contours, velocity contours, and flow patterns around the vehicle. The model used in this study is a sedan car with four different configurations: without a spoiler, with a flat spoiler and with an upward-tilted spoiler. The results indicate that Spoiler model 2 achieves an average drag coefficient reduction of approximately 19.8% compared to non-spoiler 1 across the tested speed range (5–25 m/s), Among all configurations, Non-Spoiler 2 produced the highest lift coefficient (1.19), suggesting the least favorable aerodynamic stability. In contrast, Spoiler 1 exhibited the lowest lift coefficient (0.22), highlighting its superior ability to minimize lift and improve overall stability performance