Time series–related methods in structural damage detection have gained increasing recognition due to their effectiveness, yet they face limitations accuracy and efficiency for data processing, particularly localization. In this study, we propose a novel method that utilizes mutative‐scale symbolic matrix, which extracts the second‐largest eigenvalue as indicator, address difficult problems of under random excitation. Unlike conventional symbolized time series method, matrix selects from...

Adaptive Cartesian grids, often accompanied by non-uniform hanging result in non-equidistant node distributions, posing numerical challenges for finite difference discretization. This work introduces a novel cell-based adaptive grids solver compressible flows using method, combined with an immersed boundary method to effectively simulate various complex flows. The algorithm selects easily locatable and retrievable neighboring cells around the grid as interpolation templates employs...

In this study, the spatial distribution of transient pressure and slipstream caused by a 1/10 scaled metro train passing through tunnel was studied with moving model test. We hereby investigate mechanism underlying mitigation on both surface wall, as well that in tunnel. Experimental results showed airshaft at different locations had relief effects. The most significant amplitude decreased 36.0% locating middle Meanwhile, speed also relieved from 0.45 to 0.36 after an airshaft. assessed...

When a moving high-speed train experiences sudden fire and is forced to stop in tunnel with shaft, the smoke transport characteristics become complex due coupled effects of train's piston effect natural extraction through posing significant risks personnel safety infrastructure. This study numerically reproduces above scenario analyze impact shaft on following fire-induced stoppage. The research utilizes renormalization group (RNG) k-ε turbulence model buoyancy correction volume heat source...

As the need for handling complex geometries in computational fluid dynamics (CFD) grows, efficient and accurate mesh generation techniques become paramount. This study presents an adaptive refinement (AMR) technology based on cell-based Cartesian grids, employing a distance-weighted least squares interpolation finite difference discretization utilizing immersed boundary methods wall boundaries. facilitates effective management of both transient steady flow problems. Validation through...

Abstract The effect of ground condition on unsteady aerodynamic performance a maglev train was numerically investigated with an IDDES (Improved Delayed Detached Eddy Simulation) method. accuracy the numerical method has been validated by wind tunnel experiments. flow structure, slipstream and force around under stationary moving conditions were compared. Track play leading role in influence wake vortex structure; structure is more complex boundary condition. Near nose point head tail...

In the structural health monitoring of vibration systems, varying excitation always affects accuracy damage identification. The proposed symbolic three-order square matrix detection method with norm as a indicator can solve difficult problem identification under ambient excitation. new sampling pattern extracts data from signals in time domain at specific intervals based on properties help autocorrelation coefficient. Then, extracted are converted into symbols and arranged matrix, Frobenius...

Based on the three-dimensional incompressible Navier-Stokes equations and standard k~ε two-equation turbulence model, flow field around train is simulated numerically in case of no wind condition. The influence head type windshield structure distribution aerodynamic drag coefficient lift are compared analyzed. results show that performance streamlined better, resistance obviously reduced, especially first car, tail car decreased significantly, vehicle by 45.9%. fully enclosed eliminates...

Abstract The effect of the ground condition on unsteady aerodynamic performance maglev train was numerically investigated with an IDDES (Improved Delayed Detached Eddy Simulation) method. accuracy numerical method has been validated by wind tunnel experiments. flow structure, slipstream and force around under stationary moving conditions were compared. Compared condition, vortex structure generated wake region is narrower higher because track. Near nose point head tail vehicles, peak value...

Abstract The relationship between the spatial cell and object is unknown for Cartesian grid using immersed boundary method. For researches about complex geometry or multi-body relative motion, generation a very time-consuming work, consumption mainly concentrated in position determination of cells, which we called type determination. In this study, based on axis-aligned bounding box method ray casting method, employed dot product painting algorithm to investigate acceleration generation....