Near-neutral drag coefficients over open-ocean waves

Form Drag on Ocean Flows

Form drag is a central process linking rough topography to ocean mixing processes. The history of the measurement of form drag in the ocean and atmosphere is reviewed. The basic equations governing form drag and its role in energy conversion are derived for a Boussinesq fluid, focusing on the case of tidal flow. Observational and numerical results are shown for stratified, tidal flow near a hea...

Observed drag coefficients in high winds in the near offshore of the South China Sea

This paper investigates the relationships between friction velocity, 10m drag coefficient, and 10m wind speed using data collected at two offshore observation towers (one over the sea and the other on an island) from seven typhoon episodes in the South China Sea from 2008 to 2014. The two towers were placed in areas with different water depths along a shore-normal line. The depth of water at th...

Surface forces and drag coefficients of microspheres near a plane surface measured with optical tweezers.

Optical tweezers are widely used to measure molecular forces in biology. Such measurements are often influenced by a nearby surface that can perturb both the calibration of the tweezers as well as the hydrodynamic forces acting on microspheres to which the biomolecules are attached. In this study, we have used a very stable optical tweezers setup employing a recently developed calibration metho...

Modeling Satellite Drag Coefficients With Response Surfaces

Thermal Radiation Drag on Neutral Objects

We compute the force on a small neutral polarizable object moving at velocity ~v relative to a photon gas equilibrated at a temperature T We find a drag force linear in ~v. Its physical basis is identical to that in recent formulations of the dissipative component of the Casimir force. We estimate the strength of this universal Casimir drag force for different dielectric response functions and ...