Design and numerical analysis of bicycle driver compartment area through CFD simulation

Abstract

Upright-seat bicycles exhibit poor aerodynamics, with both rider and bicycle generating significant drag intensified by wind resistance, cold air, and rainfall. This research's aim involves designing and evaluating a bicycle compartment through CFD simulation. Beginning with a standard upright mountain bike model, six conceptual models serve to assess drag, lift, and streamline efficiency. Model 0 (original) provides baseline aerodynamics, indicating a drag coefficient of 0.52, closely aligning with the experimentally measured 0.5. Modifications initiate with Model 1, where rounded frontal corners decrease lift and drag. Model 3 achieves further drag reduction to 0.437 by increasing the rounding radius. Model 4 includes a 350 mm vertical vortex splitter, resulting in a drag coefficient of 0.425. Model 5 integrates horizontal and vertical splitters with chamfering and slanting, while Model 6 adds a rear teardrop angle, enhancing streamlining and reducing recirculation, yielding a drag coefficient of 0.295. Experimental validation in a wind tunnel records a drag coefficient of 0.311, reflecting a 5.42% error due to wind tunnel limitations. Model 6 emerges as the most aerodynamically efficient design.

Keywords

• Aerodynamics
• Compartment
• Drag and lift coefficient
• Flow stream
• Vortex splitter