Search arXivSearch

arXiv · 2005.04691

On modelling bicycle power for velodromes: Part I: Formulation for individual pursuits

Abstract

For a moving bicycle, the power can be modelled as a response to the propulsion of the centre of mass of the bicycle-cyclist system. On a velodrome, an accurate modelling of power requires a distinction between the trajectory of the wheels and the trajectory of the centre of mass. We formulate and examine an individual-pursuit model that takes into account the aforementioned distinction. In doing so, we provide details of the invoked physical principles and mathematical derivations, with an emphasis on their limitations. We assume that a velodrome consists of two parallel straights and two semicircular arcs. We neglect the effects of the track inclination along the straights and assume the track inclination along the curves to be constant. For either segment, we consider two distinct black-line speeds. For the latter, the lean-angle expression is derived based on a noninertial frame of the cyclist. Among conclusions quantified by this model is the fact that a constant-cadence approach to an individual pursuit does not minimize the required power.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Michael A. Slawinski, Raphaël A. Slawinski, Theodore Stanoev. 2020-09-03. On modelling bicycle power for velodromes: Part I: Formulation for individual pursuits. https://arxiv.org/abs/2005.04691

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

Understanding Quaternions and the Dirac Belt Trick

The Dirac belt trick is often employed in physics classrooms to show that a $2π$ rotation is not topologically equivalent to the absence of rotation whereas a $4π$ rotation is, mirroring a key property of quaternions and their isomorphic cousins, spinors. The belt trick can leave the student wondering if a real understanding of quaternions and spinors has been achieved, or if the trick is just an amusing analogy. The goal of this paper is to demystify the belt trick and to show that it implies an underlying \emph{four-dimensional} parameter space for rotations that is simply connected. An investigation into the geometry of this four-dimensional space leads directly to the system of quaternions, and to an interpretation of three-dimensional vectors as the generators of rotations in this larger four-dimensional world. The paper also shows why quaternions are the natural extension of complex numbers to four dimensions. The level of the paper is suitable for undergraduate students of physics.

physics.pop-ph

Project Setu: 3D Multi-Physics Design and Scaled Structural Analysis for a Relativistic Lightsail Architecture

Deep-space exploration beyond the solar system requires eliminating chemical propellant mass penalties to achieve relativistic flight velocities (0.166c at 180 s, reaching the mission target of 0.20c at 227 s). This study presents a 3D multi-physics numerical framework for a 4.0-meter circular lightsail propelled by a 100 GW ground laser array, coupling 3D Maxwell FDTD wave optics, non-linear membrane mechanics, and Stefan-Boltzmann thermal radiation in ANSYS Mechanical APDL and Ansys Lumerical. A four-level grid convergence study establishes numerical independence with an ASME GCI_21 of 0.13%, resolving peak membrane stresses of 530.88 MPa with a 3.77x safety factor against stoichiometric Si3N4 tensile failure. With optical absorption constrained to 10 ppm (A = 1.0 x 10^-5), the steady-state core temperature stabilizes at 923.02 K (0.44% deviation from radiation theory), maintaining a +1,247 K margin below sublimation, while fundamental drumhead modal resonance (7.92 Hz) provides a 7.92x safety buffer against laser jitter. The electrodynamic radiation pressure formulation is cross-verified against published flight telemetry from JAXA IKAROS and NASA LightSail 2 within 0.12% and 2.13%, confirming classical momentum transfer modeling across solar and beamed propulsion regimes.

physics.pop-ph

Sunsets, tall buildings and the Earth's radius

It is shown how repeated observations of the sunset from various points up a tall building can be used to determine the Earth's radius. The same observations can also be used, at some latitudes, to deduce an approximate value for the amount of atmospheric refraction at the horizon.

physics.pop-ph