The dynamic stability of a fully faired single-track human-powered vehicle.

摘要

The primary limiting factor of the attainable speed of a human powered vehicle (HPV) is its aerodynamic drag, which can be reduced by fully enclosing the vehicle in a fairing. Employing fairings on single track vehicles can make them difficult to control in open road riding conditions, as significant aerodynamic forces may exist.; It is presumed that vehicle design parameters can be manipulated to improve stability in the presence of aerodynamic forces. This project analyzes each design parameter of a single-track vehicle with the goal of learning its impact on stability. For those that play a significant role in stability, the optimum combination is sought.; A mathematical model of a single track vehicle is presented. Equations of motion are developed, and are solved numerically to predict the vehicle's response to external inputs, including rider control. Open road riding conditions are modeled in the form of a fully faired HPV passing a large truck in the opposite direction on a narrow two-lane road. Computational fluid dynamics is used to obtain a time dependent solution, which includes the aerodynamic forces on the fairing.; A parameterization is performed, where the stability of the vehicle is assessed as each design parameter is varied over a prescribed range. The criterion is the maximum path divergence predicted by the mathematical model. For the design parameters crucial to stability, an optimization is performed, resulting in the optimum vehicle design.