Fast numerics for the spin orbit equation with realistic tidal dissipation and constant eccentricity     

Michele Bartuccelli  Jonathan Deane  Guido Gentile 《Celestial Mechanics and Dynamical Astronomy》2017,128(4):453-473

We present an algorithm for the rapid numerical integration of a time-periodic ODE with a small dissipation term that is \(C^1\) in the velocity. Such an ODE arises as a model of spin–orbit coupling in a star/planet system, and the motivation for devising a fast algorithm for its solution comes from the desire to estimate probability of capture in various solutions, via Monte Carlo simulation: the integration times are very long, since we are interested in phenomena occurring on timescales of the order of \(10^6\)–\(10^7\) years. The proposed algorithm is based on the high-order Euler method which was described in Bartuccelli et al. (Celest Mech Dyn Astron 121(3):233–260, 2015), and it requires computer algebra to set up the code for its implementation. The payoff is an overall increase in speed by a factor of about 7.5 compared to standard numerical methods. Means for accelerating the purely numerical computation are also discussed.  相似文献   

A 1D P-wave velocity model of the Gargano promontory (south-eastern Italy)     

Salvatore de Lorenzo  Maddalena Michele  Antonio Emolo  Andrea Tallarico 《Journal of Seismology》2017,21(4):909-919

We investigate the elastic properties of the crust in the Gargano promontory, located in the northern part of the Apulia region (Southeastern Italy). Starting on April, 2013, a local-scale seismic network, composed of 12 short-period (1 Hz) seismic stations, was deployed on the Gargano promontory. Starting on October, 2013, the network was integrated with the recordings of nine seismic stations managed by the Italian Institute of Geophysics and Volcanology (INGV). The network recorded more than 1200 seismic events in about 15 months of data acquisition, with more than 700 small magnitude events localized in the Gargano promontory and surrounding areas. A Wadati-modified method allowed us to infer V_P/V_S = 1.73 for the area. A subset of about 400 events having a relatively smaller azimuthal gap (<200°) was selected to calibrate a 1D P-wave velocity model of the area, using the VELEST inversion code. The preferred model was obtained from the average of ten velocity models, each of them representing the inversion result from given initial velocity models, calibrated on previous geological and geophysical studies in the area. The results obtained under the assumption that V_P could decrease with depth are unstable, with very different depths of the top of low-velocity layers. Therefore, the velocity model was obtained from the average of the results obtained under the assumption that V_P cannot decrease with depth. A strong reduction of both RMS (about 58%) and errors on the location of the events was obtained with respect to the starting model. The final velocity model shows a strong velocity gradient in the upper 5 km of the crust and a small increase (from 6.7 to 7 km) at 30 km of depth. The epicenters of relocated events do not show clear correlations with the surface projection of known seismic faults. A cluster of the epicenters of the relocated events intersects almost perpendicularly the Candelaro fault trace at the surface.  相似文献   

Simulating geophysical models through fractal algorithms          下载免费PDF全文

Michele De Stefano 《Geophysical Prospecting》2018,66(1):26-33

I present an algorithm, borrowed from the computer graphics industry, that is able to efficiently and effectively simulate pseudo‐realistic topographies and three‐dimensional geophysical models. It has been widely exploited in the movie industry for generating artificial landscapes and for simulating the surface of planets. The geophysical applications are manifold: simulation for testing inversion algorithms, interpolation, and upscaling are only some of the possibilities.  相似文献   

Use of ACRU,a distributed hydrological model,to evaluate how errors from downscaled rainfall are propagated in simulated runoff in uMngeni catchment,South Africa     

Samuel Kusangaya  Michele Warburton  Emma Archer van Garderen 《水文科学杂志》2017,62(12):1995-2011

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Analytical model for the out‐of‐plane response of vertically spanning unreinforced masonry walls          下载免费PDF全文

Michele Godio  Katrin Beyer 《地震工程与结构动力学》2017,46(15):2757-2776

An analytical model describing the flexural response of vertically spanning out‐of‐plane loaded unreinforced masonry walls is presented in this paper. The model is based on the second‐order Euler‐Bernoulli beam theory and captures important characteristics of the out‐of‐plane response of masonry walls that have been observed in experimental tests and from numerical studies but for which an analytical solution was still lacking: the onset and the evolution of cracking, the peak strength of the out‐of‐plane loaded walls, and the softening of the response due to P ?Δ effects. The model is validated against experimental results, and the comparison shows that the model captures both the prepeak and postpeak response of the walls. From the analytical model of the force‐displacement curve, a formula for the maximum out‐of‐plane strength of the walls is derived, which can be directly applied in engineering practice.  相似文献   

Model-based characterization of permeability damage control through inhibitor injection under parametric uncertainty     

Mahmudova  Ayisha  Borsi  Iacopo  Porta  Giovanni Michele 《Computational Geosciences》2022,26(5):1119-1134

Computational Geosciences - Damage in subsurface formations caused by mineral precipitation decreases the porosity and permeability, eventually reducing the production rate of wells in plants...  相似文献