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Reconstructing urban wind flows for urban air mobility using reduced-order data assimilation

Mounir Chrit

Accepted Manuscript , doi: 10.1016/j.taml.2023.100451

[Abstract] (0) [PDF 2096KB] (0)

Abstract:
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.

Effect of wall friction on oscillation of velocity at the head of the gravity current

Jinichi Koue

Accepted Manuscript , doi: 10.1016/j.taml.2023.100439

[Abstract] (0) [PDF 2108KB] (0)

Abstract:
Velocity oscillations at the head of the gravity current were investigated in experiments and numerical simulations of a locked-exchange flow. A comparison of the experimental and numerical simulations showed that the depth and volume of the released fluid affected the oscillations in the velocity of the gravity current. At the initial stage, the head moved forward at a constant velocity, and velocity oscillations occurred. The head maximum thickness increased at the same time as the head, which did not have a round, and accumulated buoyant fluid due to the buoyancy effect intrusion force. The period of accumulation and release of the buoyant fluid was almost the same as that observed for the head movement velocity; the head movement velocity was faster when the buoyant fluid accumulated and slower when it was released. At the viscous stage, the forward velocity decreased proportionally to the power of 1/2 of time, since the head was not disturbed from behind. As the mass concentration at the head decreased, the gravity current was slowed by the viscous stage in its effect. At the viscous stage, the mass concentration at the head was no longer present, and the velocity oscillations also decreased.

Interactions between a central bubble and a surrounding bubble cluster

A-Man Zhang, Shi-Min Li, Pu Cui, Shuai Li, and Yun-Long Liu

Accepted Manuscript , doi: 10.1016/j.taml.2023.100438

[Abstract] (0) [PDF 2033KB] (0)

Abstract:
The interaction of multiple bubbles is a complex physical problem. A simplified case of multiple bubbles is studied theoretically with a bubble located at the center of a circular bubble cluster. All bubbles in the cluster are equally spaced and own the same initial conditions as the central bubble. The unified theory for bubble dynamics (Zhang et al. arXiv:2301.13698) is applied to model the interaction between the central bubble and the circular bubble cluster. To account for the effect of the propagation time of pressure waves, the emission source of the wave is obtained by interpolating the physical information on the time axis. An underwater explosion experiment with two bubbles of different scales is used to validate the theoretical model. The effect of the bubble cluster with a variation in scale on the pulsation characteristics of the central bubble is studied.

Sound absorbing properties of spiral metasurfaces inspired by micro-perforated plates

Han Zhang, Pengxiang Hao, Huilan Wu, Zhenyuan Lin, Chengpeng Hao, Zhengpan Qi, Ning Hu

Accepted Manuscript , doi: 10.1016/j.taml.2023.100437

[Abstract] (0) [PDF 1596KB] (0)

Abstract:
As a kind of classical low-frequency sound-absorbing material, the microperforated plate (MPP) has been widely used. Here, we inspired by the sound absorption mechanism of the MPP, a spiral metasurface (SM) is designed and the analytical solution of acoustic impedance and sound absorption coefficient are obtained. The relationship between the sound absorption properties of the MPP and the SM with their own structures is systematically studied, and the analytical solutions are used to optimise the structure. It is concluded that the MPP and the SM of the same thickness achieve effective absorption in the frequency range between 390-900 Hz and 1920-4266 Hz, with a total thickness less than 1/6 of the wavelength. Meanwhile, the numerical calculation shows that the MPP and SM can match well with the background medium in the effective rang. Our study provides new insights into the design methods of sound-absorbing materials and is potentially suitable for many acoustic engineering applications.

Parameter identification for a damage phase field model using a physics-informed neural network

Carlos J. G. Rojas, Jos L. Boldrini, Marco L. Bittencourt

Accepted Manuscript , doi: 10.1016/j.taml.2023.100450

[Abstract] (0) [PDF 4156KB] (0)

Abstract:
This work applies concepts of artificial neural networks to identify the parameters of a mathematical model based on phase fields for damage and fracture. Damage mechanics is the part of the continuum mechanics that models the effects of micro-defect formation using state variables at the macroscopic level. The equations that define the model are derived from fundamental laws of physics and provide important relationships among state variables. Simulations using the model considered in this work produce good qualitative and quantitative results, but many parameters must be adjusted to reproduce certain material behavior. The identification of model parameters is considered by solving an inverse problem that uses pseudo-experimental data to find the best values that fit the data. We apply physics informed neural network and combine some classical estimation methods to identify the material parameters that appear in the damage equation of the model. Our strategy consists of a neural network that acts as an approximating function of the damage evolution with output regularized using the residue of the differential equation. Three stages of optimization seek the best possible values for the neural network and the material parameters. The training alternates between the fitting of only the pseudo-experimental data or the total loss that includes the regularizing terms. We test the robustness of the method to noisy data and its generalization capabilities using a simple physical case for the damage model. This procedure deals better with noisy data in comparison with a more standard PDE-constrained optimization method, and it also provides good approximations of the material parameters and the evolution of damage.

A reconfigurable dynamic Bayesian network for digital twin modeling of structures with multiple damage modes

Yumei Ye, Qiang Yang, Jingang Zhang, Songhe Meng, Jun Wang, Xia Tang

Accepted Manuscript , doi: 10.1016/j.taml.2023.100440

[Abstract] (0) [PDF 3768KB] (0)

Abstract:
Dynamic Bayesian networks (DBNs) are commonly employed for structural digital twin modeling. At present, most researches only consider single damage mode tracking. It is not sufficient for a reusable spacecraft as various damage modes may occur during its service life. A reconfigurable DBN method is proposed in this paper. The structure of the DBN can be updated dynamically to describe the interactions between different damages. Two common damages (fatigue and bolt loosening) for a spacecraft structure are considered in a numerical example. The results show that the reconfigurable DBN can accurately predict the acceleration phenomenon of crack growth caused by bolt loosening while the DBN with time-invariant structure cannot, even with enough updates. The definition of interaction coefficients makes the reconfigurable DBN easy to track multiple damages and be extended to more complex problems. The method also has a good physical interpretability as the reconfiguration of DBN corresponds to a specific mechanism. Satisfactory predictions do not require precise knowledge of reconfiguration conditions, making the method more practical.

Equation governing the probability density evolution of multi-dimensional linear fractional differential systems subject to Gaussian white noise

Yi Luo, Meng-Ze Lyu, Jian-Bing Chen, Pol D. Spanos

Accepted Manuscript , doi: 10.1016/j.taml.2023.100436

[Abstract] (0) [PDF 2122KB] (0)

Abstract:
Stochastic fractional differential systems are important and useful in the mathematics, physics, and engineering fields. However, the determination of their probabilistic responses is difficult due to their nonMarkovian property. The recently developed globally-evolving-based generalized density evolution equation (GE-GDEE), which is a unified partial differential equation (PDE) governing the transient probability density function (PDF) of a generic path-continuous process, including non-Markovian ones, provides a feasible tool to solve this problem. In the paper, the GE-GDEE for multi-dimensional linear fractional differential systems subject to Gaussian white noise is established. In particular, it is proved that in the GE-GDEE corresponding to the state-quantities of interest, the intrinsic drift coefficient is a time-varying linear function, and can be analytically determined. In this sense, an alternative low-dimensional equivalent linear integer-order differential system with exact closed-form coefficients for the original highdimensional linear fractional differential system can be constructed such that their transient PDFs are identical. Specifically, for a multi-dimensional linear fractional differential system, if only one or two quantities are of interest, GE-GDEE is only in one or two dimensions, and the surrogate system would be a one- or two-dimensional linear integer-order system. Several examples are studied to assess the merit of the proposed method. Though presently the closed-form intrinsic drift coefficient is only available for linear stochastic fractional differential systems, the findings in the present paper provide a remarkable demonstration on the existence and eligibility of GE-GDEE for the case that the original high-dimensional system itself is non-Markovian, and provide insights for the physical-mechanism-informed determination of intrinsic drift and diffusion coefficients of GE-GDEE of more generic complex nonlinear systems.

An operator methodology for the global dynamic analysis of stochastic nonlinear systems

Kaio C. B. Benedetti, Paulo B. Gonçalves, Stefano Lenci, Giuseppe Rega

Accepted Manuscript , doi: 10.1016/j.taml.2022.100419

[Abstract] (78) [PDF 1634KB] (2)

Abstract:
In a global dynamic analysis, the coexisting attractors and their basins are the main tools to understand the system behavior and safety. However, both basins and attractors can be drastically influenced by uncertainties. The aim of this work is to illustrate a methodology for the global dynamic analysis of nondeterministic dynamical systems with competing attractors. Accordingly, analytical and numerical tools for calculation of nondeterministic global structures, namely attractors and basins, are proposed. First, based on the definition of the Perron-Frobenius, Koopman and Foias linear operators, a global dynamic description through phase-space operators is presented for both deterministic and nondeterministic cases. In this context, the stochastic basins of attraction and attractors’ distributions replace the usual basin and attractor concepts. Then, numerical implementation of these concepts is accomplished via an adaptative phase-space discretization strategy based on the classical Ulam method. Sample results of the methodology are presented for a canonical dynamical system.

Aerodynamic shape and drag scaling law of a flexible fibre in a flowing medium

Bo-Hua Sun, Xiao-Lin Guo

Accepted Manuscript , doi: 10.1016/j.taml.2022.100397

[Abstract] (62) [PDF 1429KB] (1)

Abstract:
The study of a flexible body immersed in a flowing medium is one of the best way to find its aerodynamic shape. This Letter revisited the problem that was first studied by Alben et al. (Nature 420, 479–481, 2002). To determine the aerodynamic shape of the fibre, a simpler approach is proposed. A universal drag scaling law is obtained and the universality of the Alben-Shelley-Zhang scaling law is confirmed by using dimensional analysis. A complete Maple code is provided for finding aerodynamic shape of the fibre in the flowing medium.

Computer simulation of Cu: ALOOH/Water in a microchannel heat sink using a porous media technique and solved by numerical analysis AGM and FEM

S.A. Abdollahi, P. Jalili, B. Jalili, H. Nourozpour, Y. Safari, P. Pasha, D. Domiri Ganji

Accepted Manuscript , doi: 10.1016/j.taml.2023.100432

[Abstract] (59) [PDF 1569KB] (0)

Abstract:
Extensive improvements in small-scale thermal systems in electronic circuits, automotive industries, and microcomputers conduct the study of microsystems as essential. Flow and thermic field characteristics of the coherent nanofluid-guided microchannel heat sink are described in this perusal. The porous media approximate was used to search the heat distribution in the expanded sheet and Cu: γ - ALOOH/Water. A hybrid blend of Boehme copper and aluminum nanoparticles is evaluated to have a cooling effect on the microchannel heat sink. By using Akbari Ganji and finite element methods, linear and non-linear differential equations as well as simple dimensionless equations have been analyzed. The purpose of this study is to investigate the fluid and thermal parameters of copper hybrid solution added to water, such as Nusselt number and Darcy number so that we can reach the best cooling of the fluid. Also, by installing a piece of fin on the wall of the heat sink, the coefficient of conductive heat transfer and displacement heat transfer with the surrounding air fluid increases, and the efficiency of the system increases. The overall results show that expanding values on the NP (Series heat transfer fluid system maximizes performance with temperatures) volume division of copper, as well as boehmite alumina particles, lead to a decrease within the stream velocity of the Cu: ALOOH/Water. Increasing the volume fraction of nanoparticles in the hybrid mixture decreases the temperature of the solid surface and the hybrid nanofluid. The Brownian movement improves as the volume percentage of nanoparticles in the hybrid mixture grows, spreading heat across the environment. As a result, heat transmission rates rise. As the Darcy number increases, the thermal field for solid sections and Cu: ALOOH/Water improves.

Predicting solutions of the stochastic fractional order dynamical system using machine learning

Zi-Fei Lin, Jia-Li Zhao, Yan-Ming Liang, Jiao-Rui Li

Accepted Manuscript , doi: 10.1016/j.taml.2023.100433

[Abstract] (57) [PDF 1182KB] (0)

Abstract:
The solution of fractional-order systems has been a complex problem for our research. Traditional methods like the predictor-corrector method and other solution steps are complicated and cumbersome to derive, which makes it more difficult for our solution efficiency. The development of machine learning and nonlinear dynamics has provided us with new ideas to solve some complex problems. Therefore, this study considers how to improve the accuracy and efficiency of the solution based on traditional methods. Finally, we propose an efficient and accurate nonlinear auto-regressive neural network for the fractional order dynamic system prediction model (FODS-NAR). First, we demonstrate by example that the FODS-NAR algorithm can predict the solution of a stochastic fractional order system. Second, we compare the FODS-NAR algorithm with the famous and good reservoir computing (RC) algorithms. We find that FODS-NAR gives more accurate predictions than the traditional RC algorithm with the same system parameters, and the residuals of the FODS-NAR algorithm are closer to 0. Consequently, we conclude that the FODS-NAR algorithm is a method with higher accuracy and prediction results closer to the state of fractional-order stochastic systems. In addition, we analyze the effects of the number of neurons and the order of delays in the FODS-NAR algorithm on the prediction results and derive a range of their optimal values.

Numerical optimisation of a classical stochastic system for targeted energy transfer

Oleg Gaidai, Yubin Gu, Yihan Xing, Junlei Wang, Daniil Yurchenko

Accepted Manuscript , doi: 10.1016/j.taml.2022.100422

[Abstract] (59) [PDF 2061KB] (0)

Abstract:
The paper studies stochastic dynamics of a two-degree-of-freedom system, where a primary linear system is connected to a nonlinear energy sink with cubic stiffness nonlinearity and viscous damping. While the primary mass is subjected to a zero-mean Gaussian white noise excitation, the main objective of this study is to maximise the efficiency of the targeted energy transfer in the system. A surrogate optimisation algorithm is proposed for this purpose and adopted for the stochastic framework. The optimisations are conducted separately for the nonlinear stiffness coefficient alone as well as for both the nonlinear stiffness and damping coefficients together. Three different optimisation cost functions, based on either energy of the system’s components or the dissipated energy, are considered. The results demonstrate some clear trends in values of the nonlinear energy sink coefficients and show the effect of different cost functions on the optimal values of the nonlinear system’s coefficients.

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Characterization methods for additive manufacturing

Huimin Xie, Zhongwei Li, Zhanwei Liu

Theoretical and Applied Mechanics Letters 13 (2023) 100415. doi: 10.1016/j.taml.2022.100415

[Abstract] (372) [PDF 515KB] (3)

Abstract:

Bayesian system identification and chaotic prediction from data for stochastic Mathieu-van der Pol-Duffing energy harvester

Di Liu, Shen Xu, Jinzhong Ma

Theoretical and Applied Mechanics Letters 13 (2023) 100412. doi: 10.1016/j.taml.2022.100412

[Abstract] (59) [PDF 1775KB] (1)

Abstract:
In this paper, the approximate Bayesian computation combines the particle swarm optimization and sequential Monte Carlo methods, which identify the parameters of the Mathieu-van der Pol-Duffing chaotic energy harvester system. Then the proposed method is applied to estimate the coefficients of the chaotic model and the response output paths of the identified coefficients compared with the observed, which verifies the effectiveness of the proposed method. Finally, a partial response sample of the regular and chaotic responses, determined by the maximum Lyapunov exponent, is applied to detect whether chaotic motion occurs in them by a 0–1 test. This paper can provide a reference for data-based parameter identification and chaotic prediction of chaotic vibration energy harvester systems.

Hopf bifurcation of nonlinear system with multisource stochastic factors

Xinyu Bai, Shaojuan Ma, Qianling Zhang, Qiyi Liu

Theoretical and Applied Mechanics Letters 13 (2023) 100417. doi: 10.1016/j.taml.2022.100417

[Abstract] (66) [PDF 1734KB] (2)

Abstract:
The article mainly explores the Hopf bifurcation of a kind of nonlinear system with Gaussian white noise excitation and bounded random parameter. Firstly, the nonlinear system with multisource stochastic factors is reduced to an equivalent deterministic nonlinear system by the sequential orthogonal decomposition method and the Karhunen–Loeve (K-L) decomposition theory. Secondly, the critical conditions about the Hopf bifurcation of the equivalent deterministic system are obtained. At the same time the influence of multisource stochastic factors on the Hopf bifurcation for the proposed system is explored. Finally, the theorical results are verified by the numerical simulations.

Path integral solutions for n-dimensional stochastic differential equations under α-stable Levy excitation

Wanrong Zan, Yong Xu, Jürgen Kurths

Theoretical and Applied Mechanics Letters 13 (2023) 100430. doi: 10.1016/j.taml.2023.100430

[Abstract] (58) [PDF 5719KB] (3)

Abstract:
In this paper, the path integral solutions for a general n-dimensional stochastic differential equations (SDEs) with -stable Lévy noise are derived and verified. Firstly, the governing equations for the solutions of n-dimensional SDEs under the excitation of -stable Lévy noise are obtained through the characteristic function of stochastic processes. Then, the short-time transition probability density function of the path integral solution is derived based on the Chapman-Kolmogorov-Smoluchowski (CKS) equation and the characteristic function, and its correctness is demonstrated by proving that it satisfies the governing equation of the solution of the SDE, which is also called the Fokker-Planck-Kolmogorov equation. Besides, illustrative examples are numerically considered for highlighting the feasibility of the proposed path integral method, and the pertinent Monte Carlo solution is also calculated to show its correctness and effectiveness.

In-situ 3D contour measurement for laser powder bed fusion based on phase guidance

Yuze Zhang, Pan Zhang, Xin Jiang, Siyuan Zhang, Kai Zhong, Zhongwei Li

Theoretical and Applied Mechanics Letters 13 (2023) 100405. doi: 10.1016/j.taml.2022.100405

[Abstract] (59) [PDF 2522KB] (1)

Abstract:
In-situ layerwise imaging measurement of laser powder bed fusion (LPBF) provides a wealth of forming and defect data which enables monitoring of components quality and powder bed homogeneity. Using high-resolution camera layerwise imaging and image processing algorithms to monitor fusion area and powder bed geometric defects has been studied by many researchers, which successfully monitored the contours of components and evaluated their accuracy. However, research for the methods of in-situ 3D contour measurement or component edge warping identification is rare. In this study, a 3D contour measurement method combining gray intensity and phase difference is proposed, and its accuracy is verified by designed experiments. The results show that the high-precision of the 3D contours can be achieved by the constructed energy minimization function. This method can detect the deviations of common geometric features as well as warpage at LPBF component edges, and provides fundamental data for in-situ quality monitoring tools.

Linear logistic regression with weight thresholding for flow regime classification of a stratified wake

Xinyi L.D. Huang, Robert F. Kunz, Xiang I.A. Yang

Theoretical and Applied Mechanics Letters 13 (2023) 100414. doi: 10.1016/j.taml.2022.100414

[Abstract] (71) [PDF 4165KB] (2)

Abstract:
A stratified wake has multiple flow regimes, and exhibits different behaviors in these regimes due to the competing physical effects of momentum and buoyancy. This work aims at automated classification of the weakly and the strongly stratified turbulence regimes based on information available in a full Reynolds stress model. First, we generate a direct numerical simulation database with Reynolds numbers from 10,000 to 50,000 and Froude numbers from 2 to 50. Order (100) independent realizations of temporally evolving wakes are computed to get converged statistics. Second, we train a linear logistic regression classifier with weight thresholding for automated flow regime classification. The classifier is designed to identify the physics critical to classification. Trained against data at one flow condition, the classifier is found to generalize well to other Reynolds and Froude numbers. The results show that the physics governing wake evolution is universal, and that the classifier captures that physics.

Slip boundary effect on the critical Reynolds number of subcritical transition in channel flow

Yue Xiao, Linsen Zhang, Jianjun Tao

Theoretical and Applied Mechanics Letters 13 (2023) 100431. doi: 10.1016/j.taml.2023.100431

[Abstract] (57) [PDF 1092KB] (1)

Abstract:
In this letter, the effect of slip boundary on the origin of subcritical transition in two-dimensional channel flows is studied numerically and theoretically. It is shown that both the positive and the negative slip lengths will increase the critical Reynolds number of localized wave packet and hence postpone the transition. By applying a variable transformation and expanding the variables about a small slip length, it is illustrated that the slip boundary effect only exists in the second and higher order modulations of the no-slip solution, and hence explains the power law found in simulations, i.e. the relative increment of the critical Reynolds number due to the slip boundary is proportional to the square of the slip length.

Modeling cell contractility responses to acoustic tweezing cytometry

Suyan Zhang, Zhenzhen Fan

Theoretical and Applied Mechanics Letters 13 (2023) 100400. doi: 10.1016/j.taml.2022.100400

[Abstract] (64) [PDF 5990KB] (1)

Abstract:
Acoustic tweezing cytometry (ATC) is a recently developed method for cell mechanics regulation. Targeted microbubbles, which are attached to integrins and subsequently the actin cytoskeleton, anchor, amplify and transmit the mechanical energy in an acoustic field inside the cells, eliciting prominent cytoskeleton contractile force increases in various cell types. We propose that a mechanochemical conversion mechanism is critical for the high efficiency of ATC to activate cell contractility responses. Our models predict key experimental observations. Moreover, we study the influences of ATC parameters (ultrasound center frequency, pulse repetition frequency, duty cycle, and acoustic pressure), cell areas, the number of ATC stimuli, and extracellular matrix rigidity on cell contractility responses to ATC. The simulation results suggest that it is large molecules, rather than small ions, that facilitate global responses to the local ATC stimulation, and the incorporation of visible stress fiber bundles improves the accuracy of modeling.

On the structure of the turbulent/non-turbulent interface in a fully developed spatially evolving axisymmetric wake

Weijun Yin, YuanLiang Xie, Xinxian Zhang, Yi Zhou

Theoretical and Applied Mechanics Letters 13 (2023) 100404. doi: 10.1016/j.taml.2022.100404

[Abstract] (68) [PDF 2800KB] (3)

Abstract:
In this work, we numerically study the structure of the turbulent/nonturbulent (T/NT) interface in a fully developed spatially evolving axisymmetric wake by means of direct numerical simulations. There is a continuous and contorted pure shear layer (PSL) adjacent to the outer edge of the T/NT interface. The local thickness of the PSL exhibits a wide range of scales (from the Kolmogorov scale to the Taylor microscale) and the conditional mean thickness with being the centerline Kolmogorov scale is the same as the viscous superlayer. In the viscous superlayer, the pure shear motions without rotation are overwhelmingly dominant. It is also demonstrated that the physics of the turbulent sublayer is closely related to the PSL with a large thickness. Another significant finding is that the time averaged area of the rotational region , and the pure shear region at different streamwise locations scale with the square of the wake-width . This study opens an avenue for a better understanding of the structures of the T/NT interface.

Noise color influence on escape times in nonlinear oscillators - experimental and numerical results

Thomas Breunung, Balakumar Balachandran

Theoretical and Applied Mechanics Letters 13 (2023) 100420. doi: 10.1016/j.taml.2022.100420

[Abstract] (61) [PDF 3221KB] (1)

Abstract:
The interplay between noise and nonlinearites can lead to escape dynamics. Associated nonlinear phenomena have been observed in various applications ranging from climatology to biology and engineering. For reasons of computational ease, in most studies, Gaussian white noise is used. However, this noise model is not physical due to the associated infinite energy content. Here, the authors present extensive experimental investigations and numerical simulations conducted to examine the impact of noise color on escape times in nonlinear oscillators. With a careful parameterization of the numerical simulations, the authors are able to make quantitative comparisons with experimental results. Through the experiments and simulations, it is illustrated that the noise color can drastically influence escape times and escape probability.

Crack propagation simulation in brittle elastic materials by a phase field method

Xingxue Lu, Cheng Li, Ying Tie, Yuliang Hou, Chuanzeng Zhang

2019, 9(6): 339-352 doi: 10.1016/j.taml.2019.06.001

[Abstract](1627) [FullText HTML](932) [PDF 3845KB](100)

Investigation on Savonius turbine technology as harvesting instrument of non-fossil energy: Technical development and potential implementation

Aditya Rio Prabowo, Dandun Mahesa Prabowoputra

2020, 10(4): 262-269 doi: 10.1016/j.taml.2020.01.034

[Abstract](1468) [FullText HTML](712) [PDF 3192KB](92)

Mechanistic Machine Learning: Theory, Methods, and Applications

2020, 10(3): 141-142 doi: 10.1016/j.taml.2020.01.041

[Abstract](9466) [FullText HTML](859) [PDF 4844KB](90)

On the Weissenberg effect of turbulence