Unravelling Mechanisms for the Formation of Amorphous Bands in B <sub>6</sub>O Under Nonhydrostatic Pressure

Abstract For an adiabatic parcel convecting up or down through the atmosphere, it is often assumed that its moist static energy (MSE) is conserved. Here, it is shown that the true conserved variable for this process is MSE minus convective available potential energy (CAPE) calculated as the integral of buoyancy from the parcel’s height to its level of neutral buoyancy and that this variable is conserved even when accounting for full moist thermodynamics and nonhydrostatic pressure forces. In the calculation of a dry convecting parcel, conservation of MSE minus CAPE gives the same answer as conservation of entropy and potential temperature, while the use of MSE alone can generate large errors. For a moist parcel, entropy and equivalent potential temperature give the same answer as MSE minus CAPE only if the parcel ascends in thermodynamic equilibrium. If the parcel ascends with a nonisothermal mixed-phase stage, these methods can give significantly different answers for the parcel buoyancy because MSE minus CAPE is conserved, while entropy and equivalent potential temperature are not.

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A New Approach to Model Numerically the Nonlinear Wave Propagation

International Journal of Computational Methods ◽

10.1142/s0219876215500310 ◽

2015 ◽

Vol 12 (05) ◽

pp. 1550031 ◽

Cited By ~ 2

Author(s):

Khouane Meftah

Keyword(s):

Moving Boundary ◽

Vertical Direction ◽

Physical Nature ◽

Breaking Waves ◽

Free Surface Flows ◽

Nonlinear Wave Propagation ◽

New Approach ◽

Nonhydrostatic Pressure ◽

Sediment Transport Equation ◽

Sandbar Migration

In order to model nonlinear breaking waves with moving boundary and coastal sandbar migration; we presented a morphodynamic model, where hydrodynamic equations (free surface flows) and sediment transport equation are solved in a coupled manner. The originality lies in the development of an innovative approach, in which, we project the horizontal velocity onto a basis functions depending only on the variable z and we calculate analytically the vertical velocity and the nonhydrostatic pressure. The choice of basis depends on the problem under consideration. This model is numerically stable because there is no mesh in the vertical direction. This model is accurate because we can directly introduce functions that best fits the physical nature of the flow. Our model is validated through laboratory measurements carried out by Dingemans [1994, J. Comput. Phys. 231, 328–344], Cox and Kobayashi [2000, J. Geophys. Res. 105(c6), 223–236. and Dette et al. [2002, Coast. Eng. 47, 137–177].

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Effects of nonhydrostatic pressure on the structural and magnetic properties of BaFe2As2

Physical Review B ◽

10.1103/physrevb.83.224526 ◽

2011 ◽

Vol 83 (22) ◽

Cited By ~ 16

Author(s):

Nicola Colonna ◽

Gianni Profeta ◽

Alessandra Continenza

Keyword(s):

Magnetic Properties ◽

Nonhydrostatic Pressure ◽

Structural And Magnetic Properties

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The use of a one-dimensional depth-averaged moment of momentum equation for the nonhydrostatic pressure condition

Canadian Journal of Civil Engineering ◽

10.1139/l96-015 ◽

1996 ◽

Vol 23 (1) ◽

pp. 150-156 ◽

Cited By ~ 6

Author(s):

Yee-Chung Jin ◽

Baozhu Li

Keyword(s):

Finite Element Method ◽

Finite Element ◽

Channel Flow ◽

Open Channel ◽

Open Channel Flow ◽

Momentum Equation ◽

Nonuniform Flow ◽

Pressure Condition ◽

Nonhydrostatic Pressure ◽

Averaged Model

A depth-averaged model formulated in the Cartesian coordinate system for curved open-channel flows is extended to solve problems where the effects of nonhydrostatic pressure distribution and nonuniform velocity distribution are significant. The nonhydrostatic pressure condition is added to the z-direction momentum equation assuming that the pressure deviation from the hydrostatic condition at the channel bed decreases linearly to the water surface. The pressure-effect terms are modified in both the moment of momentum and momentum equations. The resulting system of nonlinear equations is solved by a finite-element method. The derived model is then applied to four sophisticated nonuniform flow experiments from the literature. A comparison of the actual experimental results with their numerical prediction results, as calculated with the model, is presented. Generally speaking, a fairly good agreement for the depth-averaged velocities as well as reasonable perturbation profiles were obtained from this comparison. Therefore, it can be said that the depth-averaged model for open-channel flow is reasonably accurate under the given conditions. Key words: open-channel flow, depth-averaged method, finite-element method, nonhydrostatic pressure, nonuniform flow.

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