Machine learning-based assessment of storm surge in the New York metropolitan area.

Storm surge generated from low-probability high-consequence tropical cyclones is a major flood hazard to the New York metropolitan area and its assessment requires a large number of storm scenarios. High-fidelity hydrodynamic numerical simulations can predict surge levels from storm scenarios. However, an accurate prediction requires a relatively fine computational grid, which is computationally expensive, especially when including wave effects.

Material and geometric effects on propulsion of a fish tail.

We investigate the effects of material flexibility and aspect ratio on the propulsion of flapping tails. The tail, which is assumed to deform in the bending direction only, is modeled using the Euler-Bernoulli beam theory. The hydrodynamic loads generated by the flapping motion are calculated using the three-dimensional unsteady vortex lattice method.

A novel imaging technique for measuring kinematics of light-weight flexible structures.

A new imaging algorithm is proposed to capture the kinematics of flexible, thin, light structures including frequencies and motion amplitudes for real time analysis. The studied case is a thin flexible beam that is preset at different angles of attack in a wind tunnel. As the angle of attack is increased beyond a critical value, the beam was observed to undergo a static deflection that is ensued by limit cycle oscillations.

The need for higher-order averaging in the stability analysis of hovering, flapping-wing flight.

Because of the relatively high flapping frequency associated with hovering insects and flapping wing micro-air vehicles (FWMAVs), dynamic stability analysis typically involves direct averaging of the time-periodic dynamics over a flapping cycle. However, direct application of the averaging theorem may lead to false conclusions about the dynamics and stability of hovering insects and FWMAVs. Higher-order averaging techniques may be needed to understand the dynamics of flapping wing flight and to analyze its stability.