We show that Coulomb drag in bilayer systems the regime of electron hydrodynamics leads to additional viscosity terms hydrodynamic equations, drag, and drag-Hall viscosities, besides well-known kinematic Hall viscosities. These arise from a change stress tensor due interlayer interactions. All four are tunable by varying applied magnetic field densities two layers. At certain ratios between lay...

A computational fluid dynamics (CFD) code has been combined with a genetic algorithm (GA) to perform a two-dimensional drag minimization on the base region of tractor trailers. Few studies have been conducted with CFD driven by a GA due to extensive run times and the general non autonomous characteristics of meshing a suitable CFD geometry. This study solves the two-dimensional Reynolds-average...

Toms (1949) discovered that if a very small amount of drag reducing polymers (DRP) are added in the flow, approximately 10 ppm by weight or less, a substancial reduction in pressure drop at a given flow rate resulted. Then, since 1948, the phenomenon of drag reduction have been studied by many researchers with the objective of understand the drag reduction mechanism. In the last decades, the dr...

Nowadays the underwater gliding after the starts and the turns plays a major role in the overall swimming performance. Hence, minimizing hydrodynamic drag during the underwater phases should be a main aim during swimming. Indeed, there are several postures that swimmers can assume during the underwater gliding, although experimental results were not conclusive concerning the best body position ...

A reactive control technique with localised actuators and sensors is used to delay the transition to turbulence in a flat-plate boundary-layer flow. Through extensive direct numerical simulations, it is shown that an adaptive technique, which computes the control law on-line, is able to significantly reduce skin-friction drag in the presence of random three-dimensional perturbation fields with ...

Conceptual wing design analysis methods are combined with numerical optimization to find minimum drag wings subject to constraints on lift, weight, pitching moment, and stall speed. Minimum drag tip extensions and winglets are compared using nonlinear optimization. The minimum drag trapezoidal tip device depends on the ratio of the maneuver lift coefficient to the cruise lift coefficient, altho...

The main resistive force in swimming is due to drag on a swimmer’s body from the water. There are two forms of drag, one is active drag (FD), which is the drag encountered while propelling the body through the water. The other is passive drag or the drag encountered while gliding during a push-off after a turn or after entering the water from the start. These different types of drag are both pr...

The physical and bio-mechanical principles that govern undulatory movement on wet surfaces have important applications in physiology, physics, and engineering. The nematode C. elegans, with its highly stereotypical and functionally distinct sinusoidal locomotory gaits, is an excellent system in which to dissect these properties. Measurements of the main forces governing the C. elegans crawling ...

Dinitrogenase reductase-activating glycohydrolase (DRAG), involved in the regulation of nitrogenase activity in Rhodospirillum rubrum, is associated with chromatophore membranes in cell extracts. We show that DRAG can be specifically released by treatment with MgGDP; other nucleotides studied had no effect. The DRAG activity released corresponds to the release of DRAG protein.

We demonstrate the feasibility of end-labeled free-solution electrophoresis (ELFSE) separation of DNA using genetically engineered protein polymers as drag-tags. Protein polymers are promising candidates for ELFSE drag-tags because their sequences and lengths are controllable not only to generate monodisperse polymers with high frictional drag, but also to meet other drag-tag requirements for h...