Abstract The removal of droplets on surfaces by an (air-) flow is relevant, e.g., for cleaning processes or to prevent corrosion damage electronic devices. Still the condition droplet movement not fully understood. Droplets start move downstream at a critical velocity v crit . For increasing velocity, this process related strong oscillation droplet. This supposed be key mechanism onset in conju...

The effect of weak buoyancy on the laminar flow of a fluid with kinematic viscosity ν, isobaric expansion coefficient β past a isothermally heated horizontal plate of length L and temperature T∞+∆T is aligned under a small angle of attack φ to the oncoming free stream (velocity U∞, temperature T∞) will be investigated in the distinguished limit of large Reynolds numbers Re with the “reduced” bu...

Free-vortex wake models are capable of providing an accurate and physically detailed representation of the main rotor wake for flight dynamics simulation. Recent advances in computing power and efficient algorithms have made it feasible to use free wakes for real-time simulation. The CHARM free-vortex wake model was integrated with the GENHEL flight dynamics simulation of the UH-60A helicopter....

Fish larvae may intercept their own wake during sharp turns, which might affect their escape performance. We analysed C-starts of larval zebrafish (Danio rerio, Hamilton, 1822) using a computational fluid dynamics approach that simulates free swimming (swimming trajectory is determined by fluid forces) by coupling hydrodynamics and body dynamics. The simulations show that fish may intercept the...

We present an experimental investigation of the flow structure and vorticity field in the wake of a NACA-0012 airfoil pitching sinusoidally at small amplitude and high reduced frequencies. Molecular tagging velocimetry is used to quantify the characteristics of the vortex array (circulation, peak vorticity, core size, spatial arrangement) and its downstream evolution over the first chord length...

The wake states resulting from the controlled oscillation of a cylinder transverse to the free stream are presented. A new wake state is revealed by instantaneous measurements of the total and vortex lift phases, and the phase-referenced, quantitative wake structure. This ‘‘intermediate wake state’’ occurs at oscillation frequencies between the previously observed lowand high-frequency states. ...

A new algorithm for ship wake detection is developed with the aim of ship heading and velocity estimation. It exploits the Radon transform and utilizes merit indexes in the intensity domain to validate the detected linear features as real components of the ship wake. Finally, ship velocity is estimated by state-of-the-art techniques of azimuth shift and Kelvin arm wavelength. The algorithm is a...

An area-efficient 60-GHz wake-up receiver (WuRx) using reconfiguration techniques of multistage low-noise amplifiers (LNAs) is presented. The gain stages of the 60-GHz LNA are reused as the envelope detectors for the wake-up receiver. Therefore, the bulky components such as extra switches between the wake-up receiver and the LNA, additional antennas, and excess input matching network can be rem...

We searched the COBE DIRBE Sky and Zodi Atlas for a wake of dust trailing Mars and for Trojan dust near Jupiter’s L5 Lagrange point. We compare the DIRBE images to a model Mars wake based on the empirical model of the Earth’s wake as seen by the DIRBE and place a 3-σ upper limit on the fractional overdensity of particles in the Mars wake of 18% of the fractional overdensity trailing the Earth. ...

A highly accurate Fourier-Chebyshev spectral collocation method has been used to simulate flow in the wake of a sphere in the Reynolds number range from 350 to 650. Flow visualizations and frequency spectra provide a glimpse of the complex vortex dynamics that are observed in the sphere wake. It is found that in addition to the vortex shedding frequency which corresponds to the shedding of larg...