Comparative study on breaking wave forces on vertical walls with cantilever surfaces

Physical experiments (at a scale of 1/20) are carried out using two different models: a vertical wall with cantilevering slab and a simple vertical wall. Tests are conducted for a range of values of water depth, wave period and wave height. The largest peak pressures were recorded at the SWL (82 pghs) on the vertical part and at the fixed corner of the cantilever slab (90 pghs). Pressure measurements and derived force calculations on the simple vertical wall were used to evaluate the existing prediction formulas. A significant effect of the cantilevering part is observed on the total horizontal force and overturning moment of a simple vertical wall. This is due to secondary impact occurring on the overhanging part by a jet climbing on the vertical part

Rapidly converging electromagnetic simulations in the entire frequency spectrum without the search for global loops

All known integral equation techniques for simulating scattering and radiation from arbitrarily shaped, perfect electrically conducting objects suffer from one or more of the following shortcomings: (i) they give rise to ill-conditioned systems when the frequency is low (ii) and/or when the discretization density is high, (iii) their applicability is limited to the quasi-static regime, (iv) they require a search for global topological loops, (v) they suffer from numerical cancelations in the solution when the frequency is very low. This work presents an equation that does not suffer from any of the above drawbacks when applied to smooth and closed objects. The new formulation is obtained starting from a Helmholtz decomposition of two discretizations of the electric field integral operator obtained by using RWGs and dual bases respectively. The new decomposition does not leverage loop and star/tree basis functions, but projectors that derive from them. Following the decomposition, the two discretizations are combined in a Calderon-like fashion resulting in a new overall equation that is shown to exhibit self-regularizing properties without suffering from the limitations of existing formulations. Numerical results show the usefulness of the proposed method both for closed and open structures

Coherence and quantum correlations measure sensitivity to dephasing channels

We introduce measures of quantum coherence as the speed of evolution of a system under decoherence. That is, coherence is the ability to estimate a dephasing channel, quantified by the quantum Fisher information. We extend the analysis to interferometric noise estimation, proving that quantum discord is the minimum sensitivity to local dephasing. A physically motivated set of free operations for discord is proposed. The amount of discord created by strictly incoherent operations is upper bounded by the initial coherence