Theoretical and Applied Mechanics Letters最新文献_第5页

Numerical study of the splashing wave induced by a seaplane using mesh-based and particle-based methods 基于网格和粒子的水上飞机飞溅波数值研究

IF 3.4 3区工程技术

Theoretical and Applied Mechanics Letters Pub Date : 2023-09-01 DOI: 10.1016/j.taml.2023.100463

Yang Xu , Peng-Nan Sun , Xiao-Ting Huang , Salvatore Marrone , Lei-Ming Geng

引用次数: 0

A dynamic-mode-decomposition-based acceleration method for unsteady adjoint equations at low Reynolds numbers 基于动态模态分解的低雷诺数非定常伴随方程加速方法

IF 3.4 3区工程技术

Theoretical and Applied Mechanics Letters Pub Date : 2023-09-01 DOI: 10.1016/j.taml.2023.100472

Wengang Chen , Jiaqing Kou , Wenkai Yang

{"title":"A dynamic-mode-decomposition-based acceleration method for unsteady adjoint equations at low Reynolds numbers","authors":"Wengang Chen , Jiaqing Kou , Wenkai Yang","doi":"10.1016/j.taml.2023.100472","DOIUrl":"https://doi.org/10.1016/j.taml.2023.100472","url":null,"abstract":"<div><p>The computational cost of unsteady adjoint equations remains high in adjoint-based unsteady aerodynamic optimization. In this letter, the solution of unsteady adjoint equations is accelerated by dynamic mode decomposition (DMD). The pseudo-time marching of every real-time step is approximated as an infinite-dimensional linear dynamical system. Thereafter, DMD is utilized to analyze the adjoint vectors sampled from these pseudo-time marching. First-order zero frequency mode is selected to accelerate the pseudo-time marching of unsteady adjoint equations in every real-time step. Through flow past a stationary circular cylinder and an unsteady aerodynamic shape optimization example, the efficiency of solving unsteady adjoint equations is significantly improved. Results show that one hundred adjoint vectors contains enough information about the pseudo-time dynamics, and the adjoint dominant mode can be precisely predicted only by five snapshots produced from the adjoint vectors, which indicates DMD analysis for pseudo-time marching of unsteady adjoint equations is efficient.</p></div>","PeriodicalId":46902,"journal":{"name":"Theoretical and Applied Mechanics Letters","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49708789","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Experimental observation on water entry of a sphere in regular wave 规则波中球入水的实验观察

IF 3.4 3区工程技术

Theoretical and Applied Mechanics Letters Pub Date : 2023-09-01 DOI: 10.1016/j.taml.2023.100473

Qian Wang, Changze Zhao, Haocheng Lu, Hua Liu

{"title":"Experimental observation on water entry of a sphere in regular wave","authors":"Qian Wang, Changze Zhao, Haocheng Lu, Hua Liu","doi":"10.1016/j.taml.2023.100473","DOIUrl":"https://doi.org/10.1016/j.taml.2023.100473","url":null,"abstract":"<div><p>This paper presents a novel experiment to observe the whole water entry process of a free-falling sphere into a regular wave. A time-accurate synchronizing system modulates the moment elaborately to ensure the sphere impacting onto the water surface at the desirable wave phase. Four high-speed cameras focus locally to measure the high-precision size of the cavity evolution. Meanwhile, the aggregated field view of the camera array covers both the splash above the free surface and the entire cavity in the wave. The detailed methodologies are described and verified for the hardware set-up and the image post-processing. The theoretical maximum deviation is 1.7% on the space scale. The integral morphology of the cavity is captured precisely in the coordinate system during the sphere penetrates through the water at four representative wave phases and the still water. The result shows that the horizontal velocity of the fluid particle in the wave impels the cavity and changes the shape distinctly. Notably, the wave motion causes the cavity to pinch off earlier at the wave trough phase and later at the wave crest phase than in the still water. The wave motion influences the falling process of the sphere slightly in the present parameters.</p></div>","PeriodicalId":46902,"journal":{"name":"Theoretical and Applied Mechanics Letters","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2095034923000442/pdfft?md5=37dbf755730aa971c0fe1120ed28267a&pid=1-s2.0-S2095034923000442-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"92101421","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Artificial boundary condition for Klein-Gordon equation by constructing mechanics structure 通过构造力学结构来求解Klein-Gordon方程的人工边界条件

IF 3.4 3区工程技术

Theoretical and Applied Mechanics Letters Pub Date : 2023-09-01 DOI: 10.1016/j.taml.2023.100459

Pang Gang , Zheng Zijun

引用次数: 0

Reseach on stability of laminated composite plate under nonlinear aerodynamic load 复合材料层合板在非线性气动载荷作用下的稳定性研究

IF 3.4 3区工程技术

Theoretical and Applied Mechanics Letters Pub Date : 2023-07-01 DOI: 10.1016/j.taml.2023.100461

The Van Tran , Quoc Hoa Pham , Nhan Thinh Hoang

引用次数: 0

The capillary pressure curves from upscaling interfacial and unsaturated flows in porous layers with vertical heterogeneity 纵向非均质多孔层中上尺度界面和非饱和流动的毛管压力曲线

IF 3.4 3区工程技术

Theoretical and Applied Mechanics Letters Pub Date : 2023-07-01 DOI: 10.1016/j.taml.2023.100467

Zhong Zheng

{"title":"The capillary pressure curves from upscaling interfacial and unsaturated flows in porous layers with vertical heterogeneity","authors":"Zhong Zheng","doi":"10.1016/j.taml.2023.100467","DOIUrl":"10.1016/j.taml.2023.100467","url":null,"abstract":"<div><p>We provide the capillary pressure curves <span><math><mrow><msub><mi>p</mi><mi>c</mi></msub><mrow><mo>(</mo><mover><mi>s</mi><mo>¯</mo></mover><mo>)</mo></mrow></mrow></math></span> as a function of the effective saturation <span><math><mover><mi>s</mi><mo>¯</mo></mover></math></span> based on the theoretical framework of upscaling unsaturated flows in vertically heterogeneous porous layers proposed recently in [1]. Based on the assumption of vertical gravitational-capillary equilibrium, the saturation distribution and profile shape of the invading fluid can be obtained by solving a nonlinear integral-differential equation. The capillary pressure curves <span><math><mrow><msub><mi>p</mi><mi>c</mi></msub><mrow><mo>(</mo><mover><mi>s</mi><mo>¯</mo></mover><mo>)</mo></mrow></mrow></math></span> can then be constructed by systematically varying the injection rate. Together with the relative permeability curves <span><math><mrow><msub><mover><mi>k</mi><mo>¯</mo></mover><mrow><mi>r</mi><mi>n</mi></mrow></msub><mrow><mo>(</mo><mover><mi>s</mi><mo>¯</mo></mover><mo>)</mo></mrow></mrow></math></span> that are already obtained in <span>[1]</span>, one can now provide quick estimates on the overall behaviours of interfacial and unsaturated flows in vertically-heterogeneous porous layers.</p></div>","PeriodicalId":46902,"journal":{"name":"Theoretical and Applied Mechanics Letters","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41796130","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Torsional postbuckling characteristics of functionally graded graphene enhanced laminated truncated conical shell with temperature dependent material properties 具有温度相关材料特性的功能梯度石墨烯增强层合截锥壳的扭转后屈曲特性

IF 3.4 3区工程技术

Theoretical and Applied Mechanics Letters Pub Date : 2023-07-01 DOI: 10.1016/j.taml.2023.100453

Hamad M. Hasan , Saad S. Alkhfaji , Sattar A. Mutlag

{"title":"Torsional postbuckling characteristics of functionally graded graphene enhanced laminated truncated conical shell with temperature dependent material properties","authors":"Hamad M. Hasan , Saad S. Alkhfaji , Sattar A. Mutlag","doi":"10.1016/j.taml.2023.100453","DOIUrl":"10.1016/j.taml.2023.100453","url":null,"abstract":"<div><p>Buckling and postbuckling characteristics of laminated graphene-enhanced composite (GEC) truncated conical shells exposed to torsion under temperature conditions using finite element method (FEM) simulation are presented in this study. In the thickness direction, the GEC layers of the conical shell are ordered in a piece-wise arrangement of functionally graded (FG) distribution, with each layer containing a variable volume fraction for graphene reinforcement. To calculate the properties of temperature-dependent material of GEC layers, the extended Halpin-Tsai micromechanical framework is used. The FEM model is verified via comparing the current results obtained with the theoretical estimates for homogeneous, laminated cylindrical, and conical shells, the FEM model is validated. The computational results show that a piece-wise FG graphene volume fraction distribution can improve the torque of critical buckling and torsional postbuckling strength. Also, the geometric parameters have a critical impact on the stability of the conical shell. However, a temperature rise can reduce the crucial torsional buckling torque as well as the GEC laminated truncated conical shell's postbuckling strength.</p></div>","PeriodicalId":46902,"journal":{"name":"Theoretical and Applied Mechanics Letters","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46691188","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

An overview of fluids mixing in T-shaped mixers t形混合器中流体混合的概述

IF 3.4 3区工程技术

Theoretical and Applied Mechanics Letters Pub Date : 2023-07-01 DOI: 10.1016/j.taml.2023.100466

Huixin Li , Duo Xu

引用次数: 0

Reconstructing urban wind flows for urban air mobility using reduced-order data assimilation 利用降阶数据同化重建城市气流以实现城市空气流动

IF 3.4 3区工程技术

Theoretical and Applied Mechanics Letters Pub Date : 2023-07-01 DOI: 10.1016/j.taml.2023.100451

Mounir Chrit

{"title":"Reconstructing urban wind flows for urban air mobility using reduced-order data assimilation","authors":"Mounir Chrit","doi":"10.1016/j.taml.2023.100451","DOIUrl":"10.1016/j.taml.2023.100451","url":null,"abstract":"<div><p>Advancements in uncrewed aircrafts and communications technologies have led to a wave of interest and investment in unmanned aircraft systems (UASs) and urban air mobility (UAM) vehicles over the past decade. To support this emerging aviation application, concepts for UAS/UAM traffic management (UTM) systems have been explored. Accurately characterizing and predicting the microscale weather conditions, winds in particular, will be critical to safe and efficient operations of the small UASs/UAM aircrafts within the UTM. This study implements a reduced order data assimilation approach to reduce discrepancies between the predicted urban wind speed with computational fluid dynamics (CFD) Reynolds-averaged Navier Stokes (RANS) model with real-world, limited and sparse observations. The developed data assimilation system is UrbanDA. These observations are simulated using a large eddy simulation (LES). The data assimilation approach is based on the time-independent variational framework and uses space reduction to reduce the memory cost of the process. This approach leads to error reduction throughout the simulated domain and the reconstructed field is different than the initial guess by ingesting wind speeds at sensor locations and hence taking into account flow unsteadiness in a time when only the mean flow quantities are resolved. Different locations where wind sensors can be installed are discussed in terms of their impact on the resulting wind field. It is shown that near-wall locations, near turbulence generation areas with high wind speeds have the highest impact. Approximating the model error with its principal mode provides a better agreement with the truth and the hazardous areas for UAS navigation increases by more than 10% as wind hazards resulting from buildings wakes are better simulated through this process.</p></div>","PeriodicalId":46902,"journal":{"name":"Theoretical and Applied Mechanics Letters","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48234507","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Assessment of the stiffened panel performance in the OTEC seawater tank design: Parametric study and sensitivity analysis OTEC海水箱加劲板性能评估:参数化研究与敏感性分析

IF 3.4 3区工程技术

Theoretical and Applied Mechanics Letters Pub Date : 2023-07-01 DOI: 10.1016/j.taml.2023.100452

Yogie Muhammad Lutfi , Ristiyanto Adiputra , Aditya Rio Prabowo , Tomoaki Utsunomiya , Erwandi Erwandi , Nurul Muhayat

{"title":"Assessment of the stiffened panel performance in the OTEC seawater tank design: Parametric study and sensitivity analysis","authors":"Yogie Muhammad Lutfi , Ristiyanto Adiputra , Aditya Rio Prabowo , Tomoaki Utsunomiya , Erwandi Erwandi , Nurul Muhayat","doi":"10.1016/j.taml.2023.100452","DOIUrl":"10.1016/j.taml.2023.100452","url":null,"abstract":"<div><p>Ocean thermal energy conversion (OTEC) is a process of generating electricity by exploiting the temperature difference between warm surface seawater and cold deep seawater. Due to the high static and dynamic pressures that are caused by seawater circulation, the stiffened panel that constitutes a seawater tank may undergo a reduction in ultimate strength. The current paper investigates the design of stiffening systems for OTEC seawater tanks by examining the effects of stiffening parameters such as stiffener sizes and span-over-bay ratio for the applied combined loadings of lateral and transverse pressure by fluid motion and axial compression due to global bending moment. The ultimate strength calculation was conducted by using the non-linear finite element method via the commercial software known as ABAQUS. The stress and deformation distribution due to pressure loads was computed in the first step and then brought to the second step, in which the axial compression was applied. The effects of pressure on the ultimate strength of the stiffener were investigated for representative stiffened panels, and the significance of the stiffener parameters was assessed by using the sensitivity analysis method. As a result, the ultimate strength was reduced by approximately 1.5% for the span-over-bay ratio of 3 and by 7% for the span-over-bay ratio of 6.</p></div>","PeriodicalId":46902,"journal":{"name":"Theoretical and Applied Mechanics Letters","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47601183","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 6