Understanding how the shape and motion of an aquatic animal affects the performance of swimming requires knowledge of the fluid forces that generate thrust and drag. These forces are poorly understood for the large diversity of animals that swim at Reynolds numbers (Re) between 10(0) and 10(2). We experimentally tested quasi-steady and unsteady blade-element models of the hydrodynamics of undul...

The International Moth dinghy is a 3.355m long single handed, una-rigged monohull dinghy. The class rules allow the use of hydrofoil that in certain wind conditions can significantly reduce resistance. A new velocity prediction program (VPP) has been developed to evaluate the impact of hydrofoil design and set-up on the performance of a Moth dinghy by simulating racing on a windward leeward cou...

In this study, a numerical computational fluid dynamics study is conducted in order to predict the aerodynamic forces on the NP car. The turbulent air flow around the car is modeled using the realizable k-ε model. First, results are validated against those presented for the Ahmed’s body. Next, the fluid flow around the car is simulated for different car speeds ( to mph) and fl...

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...

In this study, a novel but simple biomimetic turbulent drag reduction topology is proposed, inspired by the special structure of shark skin. Two effective, skin-inspired, ribletted surfaces were designed, their topologies optimized, and excellent performances verified large eddy simulation. The designed riblets showed higher behavior, e.g., 21.45% at Re = 40,459, compared with other experimenta...

Different from conventional streamwise-aligned riblets, converging and diverging (C–D) riblets are arranged obliquely along the main-flow direction, intending to induce a large-scale secondary flow that modulates or controls existing vortical structures in wall turbulence. In this study, we perform direct numerical simulations of turbulent over C–D at low Reynolds number investigate impacts on ...

G-quadruplexes represent a novelty for molecular biology. Their role inside the cell remains mysterious. We investigate a possible correlation with mRNA localization. In particular, we hypothesize that G-quadruplexes influence fluid dynamics. Localization of mRNA molecules within the cytoplasm recently emerged as a prevalent mechanism for cell polarization, thus underlying developmental process...

The hydrodynamic and thermal lattice Boltzmann methods are applied to investigate the turbulent convective heat transfer in the wavy channel flows. In this study, the turbulent phenomena are modeling by large-eddy simulations with the Smagorinsky model. As a benchmark, the laminar and turbulent backward-facing step flows are simulated first. The results give good agreement with other numerical ...