CFD Analysis Of Drag Force On A Flat Plate

Abstract

This study presents a Computational Fluid Dynamics (CFD) analysis of airflow over a flat plate to investigate the effect of inlet velocity on flow characteristics and drag force. Numerical simulations were performed using ANSYS Fluent 2026 R1 with inlet velocities of 5 m/s, 10 m/s, and 15 m/s. A two-dimensional computational domain containing a 100 mm long and 5 mm thick flat plate was developed, and a grid independence test was conducted using mesh sizes of 10 mm, 8 mm, and 5 mm. The 5 mm mesh was selected for the subsequent simulations due to its more stable and accurate solution. The results show that increasing the inlet velocity significantly influences the velocity distribution, pressure distribution, wake development, Reynolds number, and drag force around the flat plate. The Reynolds number increased from 34,237 at 5 m/s to 102,711 at 15 m/s, while the drag force increased from 0.109 N to 0.970 N. Meanwhile, the drag coefficient remained approximately constant at 0.007 for all investigated cases. At the highest inlet velocity, stronger velocity and pressure gradients as well as a longer and more pronounced wake region were observed. Overall, the numerical results demonstrate that increasing inlet velocity leads to greater flow disturbance and a substantial increase in drag force, consistent with the theoretical relationship between drag force and the square of flow velocity.