Development of a Land Subsidence Forecasting Model Using Small Baseline Subset—Differential Synthetic Aperture Radar Interferometry and Particle Swarm Optimization—Random Forest (Case Study: Tehran-Karaj-Shahriyar Aquifer,Iran)     

Chatrsimab  Zahra  Alesheikh  Ali Asghar  Voosoghi  Behzad  Behzadi  Saeed  Modiri  Mehdi 《Doklady Earth Sciences》2020,494(1):718-725

Doklady Earth Sciences - Land subsidence, as a dangerous environmental issue, causes serious damages to farms and urban infrastructure. In this regards, this research was conducted with aimed to...  相似文献   

A Unified Computational Method for Simulating Dynamic Behavior of Planing Vessels     

Mohammad Saeed SEIF  Ebrahim JAHANBAKHSH  Roozbeh PANAHI  Mohammad Hossein KARIMI 《中国海洋工程》2009,23(3):517-528

High speed planing hulls have complex hydrodynamic behaviors. The trim angle and drafts are very sensitive to speed and location of the center of gravity. Therefore, motion simulation for such vessels needs a strong coupling between rigid body motions and hydrodynamic analysis. In addition, free surface should be predicted with good accuracy for each time step. In this paper, velocity and pressure fields are coupled by use of the fractional step method. On the basis of integration of the two-phase viscous f...  相似文献   

Towards simulation of 3D nonlinear high-speed vessels motion     

Roozbeh Panahi  Ebrahim Jahanbakhsh  Mohammad Saeed Seif 《Ocean Engineering》2009,36(3-4):256-265

A numerical simulation algorithm based on the finite volume discretisation is presented for analyzing ship motions. The algorithm employs a fractional step method to deal with the coupling between the pressure and velocity fields. The free surface capturing is fulfilled by using a volume of fluid method in which the interface between the liquid (water) and gas (air) phases are computed by solving a scalar transport equation for the volume fraction of the liquid phase. The computed velocity field is employed to evaluate the acting forces and moments on the vessel. Using the strategy of boundary-fitted body-attached mesh and calculating all six degrees-of-freedom of motion in each time step, time history of ship motions including displacements, velocities and accelerations are evaluated.To verify the proposed algorithm, a series of verification tests are conducted. First, a two-dimensional asymmetrical wedge slamming is simulated as a simple type of a common case for high-speed vessels. Then, the steady-state forward motion of a high-speed planing catamaran is investigated. Results of both test cases show good agreement with experimental data. It is concluded that the proposed algorithm can be a promising strategy for both performance prediction and design of high-speed vessels.  相似文献   

Optimal shape design of defense structures for minimizing short wave impact     

D. Isebe  P. Azerad  B. Mohammadi  F. Bouchette 《Coastal Engineering》2008

The paper presents coastal structures design in the presence of waves by the minimization of a cost function. It aims to show that shape optimization can be efficiently applied to ocean engineering. This is an underlying guiding principle for the design of harbors or offshore breakwaters. We compute the solution of a specific simplified boundary value problem describing the short wave propagation toward a vertical sea cliff or vertical wall and modify accordingly the shape of defense structures in order to minimize a pre-defined cost function taking into account the strength (energy) of the water waves. The optimization procedure relies on a global semi-deterministic search algorithm able to escape from local minima.  相似文献