The enhancement of heat transfer by an electric field to a spherical droplet translating at intermediate Reynolds number is numerically investigated using a finite volume method. Two heat transfer limits are considered. The first limit is the external problem where the bulk of the resistance is assumed to be in the continuous phase. Results show that the external Nusselt number significantly in...

In this study, selected types of grasses were studied to determine their hydraulic roughness coefficient and select the most suitable grass for erosion control. The experiments performed in twelve trapezoidal open channels measuring 5 m x 0.12 0.03 at different flow depths (0.001m, 0.002m, 0.003m, 0.004m 0.005m) varying bed slope (0.2%, 0.3%, 0.4%). Overall, Bahama showed highest Manning’s n-va...

Direct numerical simulations of flow past cactus-shaped cylinders are performed at Reynolds numbers of 20, 100, and 300. The results are contrasted to those from smooth cylinders at the same Reynolds numbers. The cavities in the cactus-shaped cylinders are seen to reduce the forces acting on them. At Reynolds number of 20, the drag is reduced by 22% due to reduction in the viscous forces. At Re...

A method is described for measuring the local drag coefficient on a long cylinder which exhibits vortex-induced vibration (VIV). Results are shown from a field experiment in which a long flexible pipe was instrumented with two-hundred and eighty fiber optic strain gauges. The measured local drag coefficients are compared to a commonly used drag coefficient prediction formula. The formula is sho...

The assessment of turbulence model performance in predicting ow elds that are directly relevant to industrial needs has become increasingly important. In aerodynamics , many problems exist for which the performance of some turbulence models is ambiguous at best and incorrect at worst. The application of many diierent turbulence models to a particular problem is a lengthy process that can lead t...

A fundamental study to characterize the flow around an oscillating cylinder in a pulsatile flow environment is investigated. This work is motivated by a new proposed design of the total artificial lung (TAL), which is envisioned to provide better gas exchange. The Navier-Stokes computations in a moving frame of reference were performed to compute the dynamic flow field surrounding the cylinder....

Computational experiments based on the direct numerical simulation of turbulent channel flow reveal that the skin friction can be reduced as much as 70% by the action of a localized steady force acting against the flow close to the wall. In addition, the excessive shear stresses observed during the laminar-to-turbulence transition can be substantially reduced. For a sustained reduction in the s...

Wave damping by vegetation has been included in many numerical models for coastal engineering primarily through a parameterized expression the wave height decay following Mendez and Losada (2004). CD is an empirical coefficient often derived from reduced-scale laboratory experiments which alpha measured directly. Multiple values of can be determined series tests given as function Reynolds numbe...

The lower limit on the drag coefficient under hurricane force winds is determined by the break-up of the air–sea interface due to Kelvin–Helmholtz instability and formation of the two-phase transition layer consisting of sea spray and air bubbles. As a consequence, a regime of marginal stability develops. In this regime, the air–sea drag coefficient is determined by the turbulence characteristi...