Article
Mathematics, Applied
Suleyman Cengizci, Omur Ugur
Summary: This computational study investigates numerical solutions of Burgers'-type equations at high Reynolds numbers. The nonlinearity becomes significant and the equations are dominated by convection, leading to spurious oscillations in solutions obtained through standard numerical methods. To address this, the Galerkin finite element formulation is stabilized using the streamline-upwind/Petrov-Galerkin method. YZ beta shock-capturing is further employed to improve solution profiles around strong gradients. The resulting nonlinear equation systems are solved using the Newton-Raphson (N-R) method, while the linearized equation systems are solved with the BiCGStab technique and ILU preconditioning.
APPLIED MATHEMATICS AND COMPUTATION
(2023)
Article
Green & Sustainable Science & Technology
J. C. C. Henriques, L. M. C. Gato, V. La Sala, A. A. D. Carrelhas
Summary: This study compares the noise emissions of a biradial turbine and a Wells turbine, and finds that the biradial turbine has significantly lower noise levels than the Wells turbine at off-design conditions for the same pneumatic power.
Article
Engineering, Multidisciplinary
Vedad Tojaga, T. Christian Gasser, Artem Kulachenko, Soren Ostlund, Adnan Ibrahimbegovic
Summary: This study introduces a three-dimensional geometrically nonlinear Reissner beam theory for modeling failure in structures and discusses its finite element implementation. The theory considers cracks through displacement discontinuities and incorporates three modes of fracture inside an element. By eliminating nodeless degrees of freedom and using an alternating minimization algorithm, a positive definite stiffness matrix is obtained. The performance of these new finite elements in numerical examples, including the fracture of random lattice structures, is demonstrated. Geometrical nonlinearity in the beam formulation is shown to be necessary for direct numerical simulations of fiber networks.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2023)
Article
Computer Science, Theory & Methods
Yanxia Li, Ke Zhao
Summary: The research on sport motional characteristic modeling in HCI field is of great significance, and a method based on multi-model feature fusion is proposed to control motion features. This method utilizes Kinect sensor to capture real-time video stream and utilizes HSV-based image segmentation to improve hand image recognition. Experimental results demonstrate the effectiveness of this method.
FUTURE GENERATION COMPUTER SYSTEMS-THE INTERNATIONAL JOURNAL OF ESCIENCE
(2021)
Article
Chemistry, Multidisciplinary
Haoyue Guo, Younghwan Pan
Summary: By examining usability definitions, collecting satisfaction questionnaires, and user interviews, a scale was developed to measure satisfaction with mid-air gestures. Through factor analysis, six latent variables were identified and a hierarchical model of influencing factors was constructed. The study shows that the influencing factors can be divided into three levels.
APPLIED SCIENCES-BASEL
(2023)
Article
Chemistry, Analytical
Fuad Al Abir, Md. Al Siam, Abu Sayeed, Md. Al Mehedi Hasan, Jungpil Shin
Summary: Air-writing is a method of writing letters or words in free space with body movements, which is sensitive to the subject and language of interest. The use of smart-bands has made air-writing recognition systems more flexible, but the variability in signal duration remains a key challenge in developing models.
Article
Geochemistry & Geophysics
C. Gowri Shankar, Manasa Ranjan Behera
Summary: The study introduces an improved method for calculating the wind drag coefficient under extreme hurricane conditions, which has shown to be more accurate in estimating storm wave heights and peak surge levels compared to two other widely used methods. This method was validated using data from Hurricanes Katrina, Rita, and Michael.
DYNAMICS OF ATMOSPHERES AND OCEANS
(2021)
Article
Engineering, Multidisciplinary
Eunjong Ahn, Hyunjun Kim, Seongwoo Gwon, Sung-Rok Oh, Cheol-Gyu Kim, Sung-Han Sim, Myoungsu Shin
Summary: This study evaluates the self-healing of in situ concrete members using a combination of air-coupled surface-wave and computer-vision techniques. Results show that specimens containing micro-capsules have superior healing performance compared to ordinary concrete specimens, with the healing rate strongly correlated with the change in crack area.
STRUCTURAL HEALTH MONITORING-AN INTERNATIONAL JOURNAL
(2022)
Article
Engineering, Marine
Yupeng Song, Jianbing Chen, John Dalsgaard Sorensen, Jie Li
Summary: This paper studies the joint probabilistic modeling of long-term wind and wave parameters in the fatigue assessment of offshore wind turbines. Data separation and segmentation are performed to develop a full probabilistic model for a site in the South China Sea. Numerical results indicate that the proposed methods can effectively deal with this problem.
Article
Engineering, Multidisciplinary
Dario Vangi, Mara Bruzzi, James Norbert Caron, Michelangelo-Santo Gulino
Summary: Gas-coupled laser acoustic detection (GCLAD) is an unestablished technique for noncontact ultrasound detection based on the interaction of laser and acoustic waves, showing high sensitivity to surface defects on metal plates, especially when perpendicular to the ultrasonic propagation direction in air. It demonstrates a major advantage of instantly inspecting an entire line rather than just a point like traditional transducers.
MEASUREMENT SCIENCE AND TECHNOLOGY
(2021)
Article
Engineering, Geological
Haojie Xing, Xiaojun Li, Hongjing Li, Aiwen Liu
Summary: The application of local artificial boundary conditions in the high-efficient spectral element method remains a topic for further study. The development of a new set of numerical schemes has shown stable and quite accurate results in spectral-element simulation of seismic wave propagation.
SOIL DYNAMICS AND EARTHQUAKE ENGINEERING
(2021)
Article
Food Science & Technology
Nittaya Junka, Chaiwat Rattanamechaiskul
Summary: The combination of fluid bed drying and n-ZnO coating system proved to be effective in controlling fungal growth in paddy before storage. Mathematical modeling helped in predicting suitable conditions for the process, and the results showed that higher hot air temperature and longer operating time decreased fungal growth and phenolic content while reducing specific energy consumption. Novel coating method for Sangyod rice has potential application in the rice industry to safeguard against fungal infection during long-term storage.
JOURNAL OF FOOD PROCESSING AND PRESERVATION
(2022)
Article
Chemistry, Multidisciplinary
George I. Koshovy, Andrii G. Koshovy
Summary: The integral equations technique has been modified for studying the scattering of electromagnetic waves by multilevel coplanar systems of zero-thickness impedance strips. The scattering problem is reformulated as second-kind regular integral equations using the Carleman regularization technique. Two novel classes of Cantor functions are presented and analyzed, which can be used to create non-classical orderings for specific multilevel coplanar strips systems. These systems have the potential to model irregular natural processes and zones in the future.
APPLIED SCIENCES-BASEL
(2023)
Article
Engineering, Electrical & Electronic
Yankai Ma, Shiwen Yang, Yikai Chen, Shi-Wei Qu, Jun Hu
Summary: An optimization technique for irregular arrays with high-directivity combining maximum entropy model is proposed. By analyzing the reduction in directivity due to relative wave path difference, a mixed integer linear programming model is introduced to achieve high directivity and low sidelobe simultaneously for tetromino-shaped irregular arrays. The proposed method outperforms state-of-the-art methods in terms of directivity by about 1 dB for a scan to 45 degrees.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2021)
Article
Construction & Building Technology
Eunjong Ahn, Hyunjun Kim, Byoungsun Park, Myoungsu Shin
Summary: This study investigated the long-term healing progress and re-healing performance of self-healing concrete using the air-coupled surface-wave method. A prediction model for healing rate was proposed, and the re-healing process showed satisfactory results in surface wave transmission recovery after the crack reopening.
CONSTRUCTION AND BUILDING MATERIALS
(2021)
Article
Mathematics, Interdisciplinary Applications
Fulin Zhang, Takashi Kuraishi, Kenji Takizawa, Tayfun E. Tezduyar
Summary: This article continues the study on wind turbine wake computation using the ST-VMS method and ST isogeometric discretization, focusing on directional preference in spatial refinement. The evaluation shows that there is a preference for refinement in the cross-flow directions.
COMPUTATIONAL MECHANICS
(2022)
Article
Mathematics, Interdisciplinary Applications
Takashi Kuraishi, Satoshi Yamasaki, Kenji Takizawa, Tayfun E. Tezduyar, Zhaojing Xu, Ryutaro Kaneko
Summary: This paper presents a space-time isogeometric analysis framework for car and tire aerodynamics. The framework addresses the complexities of geometries, tire rotation, accurate representation of boundary layers, turbulent flow, aerodynamic interaction, NURBS mesh generation, and mesh quality improvement. The framework integrates various methods and techniques to achieve accurate computations at high resolutions.
COMPUTATIONAL MECHANICS
(2022)
Article
Mathematics, Interdisciplinary Applications
Yasutoshi Taniguchi, Kenji Takizawa, Yuto Otoguro, Tayfun E. Tezduyar
Summary: This article presents a hyperelastic extended Kirchhoff-Love shell model that takes into account the out-of-plane normal stress. The derivation of the new model is provided, with a focus on the mechanics of out-of-plane deformation. By considering the distribution of out-of-plane normal stress, the accuracy of calculating the deformed-configuration out-of-plane position and the nonlinear response of the shell are improved. The new model allows for specifying the traction acting on the shell on the upper and lower surfaces separately, without relying on the midsurface location. Test computations for different shell deformations and material models are also presented.
COMPUTATIONAL MECHANICS
(2022)
Article
Mathematics, Interdisciplinary Applications
Takashi Kuraishi, Zhaojing Xu, Kenji Takizawa, Tayfun E. Tezduyar, Satoshi Yamasaki
Summary: This study presents a high-resolution space-time isogeometric analysis method for car and tire aerodynamics, which accurately captures the tire geometry, road contact, and tire deformation and rotation. The method combines various techniques and methods to achieve a detailed representation of the flow near the tire and reduce computational cost and data storage burden.
COMPUTATIONAL MECHANICS
(2022)
Article
Mathematics, Interdisciplinary Applications
Yang Liu, Kenji Takizawa, Tayfun E. Tezduyar, Takashi Kuraishi, Yufei Zhang
Summary: This article introduces a Carrier-Domain Method (CDM) for high-resolution computation of time-periodic long-wake flows, which is cost-effective and practical. The CDM utilizes a moving computational domain and high-resolution moving mesh to compute long-wake flows, providing a more cost-effective approach compared to fixed meshes. The results of the study demonstrate the effectiveness of CDM in high-resolution computation of time-periodic long-wake flows.
COMPUTATIONAL MECHANICS
(2023)
Article
Mathematics, Interdisciplinary Applications
Takuya Terahara, Kenji Takizawa, Tayfun E. Tezduyar
Summary: We introduce a T-splines computational method and its implementation that allows for connecting structures of different parametric dimensions with continuity and smoothness. We derive the basis functions for connecting structures with 2D and 1D parametric dimensions, involving proper selection of a scale factor for the knot vector of the 1D structure. The method can be extended to achieve higher-order continuity when needed.
COMPUTATIONAL MECHANICS
(2023)
Article
Mathematics, Interdisciplinary Applications
Takuya Terahara, Kenji Takizawa, Reha Avsar, Tayfun E. E. Tezduyar
Summary: In this article, the authors present the T-splines computational method for spacecraft parachute structural mechanics computations. The method allows for connecting structures with different parametric dimensions and ensures continuity and smoothness. The effectiveness of the method is demonstrated through computations involving both membrane and shell models of the parachute canopy fabric.
COMPUTATIONAL MECHANICS
(2023)
Article
Mathematics, Applied
Kenji Takizawa, Yuri Bazilevs, Tayfun E. Tezduyar
Summary: This article provides a brief summary of the research developments in Isogeometric Analysis (IGA) for Computational Fluid Dynamics (CFD), focusing on its application in complex, unsteady, and turbulent flows.
MATHEMATICAL MODELS & METHODS IN APPLIED SCIENCES
(2022)
Article
Energy & Fuels
Valerio Francesco Barnabei, Fabrizio Bonacina, Alessandro Corsini, Francesco Aldo Tucci, Roberto Santilli
Summary: This paper proposes an unsupervised anomaly detection framework for gas gensets in District Heating networks based on SCADA data. The framework utilizes multivariate Machine-Learning regression models and post-processes the model residuals with a sliding threshold approach. The results demonstrate the successful detection of anomalies related to unscheduled downtime.
Article
Energy & Fuels
Eric Stefan Miele, Nicole Ludwig, Alessandro Corsini
Summary: This study investigates a multi-modal approach for wind power forecasting by considering turbine-level time series collected from SCADA systems and high-resolution Numerical Weather Prediction maps. A neural architecture based on stacked Recurrent Neural Networks is proposed to process and combine different data sources containing spatio-temporal patterns. The results show that a subset of features associated with all wind directions can produce more accurate forecasts with respect to full grids and reduce computation times.
Article
Mathematics, Applied
Kenji Takizawa, Yuto Otoguro, Tayfun E. Tezduyar
Summary: The stabilization parameters of certain methods involve two local length scales - advection and diffusion length scales. The advection length scale is always in the flow direction, while the diffusion length scale is typically dependent on the element geometry. However, there is a justification for making the diffusion length scale also direction-dependent to account for spatial variation of the solution. To achieve this, a direction-dependent diffusion length scale calculated from the strain-rate tensor is introduced.
MATHEMATICAL MODELS & METHODS IN APPLIED SCIENCES
(2023)
Review
Mechanics
Yuri Bazilevs, Kenji Takizawa, Tayfun E. Tezduyar, Artem Korobenko, Takashi Kuraishi, Yuto Otoguro
Summary: The superior accuracy isogeometric analysis (IGA) has brought higher fidelity to computational aerodynamics in fluid and solid mechanics. The IGA achieves increased accuracy in flow solution, problem geometry representation, and representation of solid surface motion in a space-time framework. IGA is part of a set of methods that have proven effective in computational aerodynamics, including complex-geometry aerodynamics. These methods can be categorized into core methods, accuracy-boosting methods, and application range-expanding methods. We provide an overview of these methods and showcase examples of their computations.
JOURNAL OF MECHANICS
(2023)
Article
Mathematics, Applied
Tayfun E. Tezduyar, Kenji Takizawa, Yuri Bazilevs
Summary: This paper provides an overview of flows with moving boundaries and interfaces (MBI), which include fluid-particle and fluid-structure interactions, multi-fluid flows, and free-surface flows. These problems are frequently encountered in engineering analysis and design, and pose computational challenges that require core computational methods and special methods. The paper focuses on isogeometric analysis, complex geometries, incompressible-flow Space-Time Variational Multiscale (ST-VMS) and Arbitrary Lagrangian-Eulerian VMS (ALE-VMS) methods, and special methods developed in connection with these core methods.
MATHEMATICAL MODELS & METHODS IN APPLIED SCIENCES
(2024)
Review
Mechanics
Takuya Terahara, Takashi Kuraishi, Kenji Takizawa, Tayfun E. Tezduyar
Summary: This article provides an overview of heart valve flow analyses using boundary layer and contact representation with space-time computational methods, overcoming challenges in maintaining high-resolution flow representation near the valve surfaces, which is important for cardiac flow simulations.
JOURNAL OF MECHANICS
(2022)
Review
Mechanics
Takashi Kuraishi, Takuya Terahara, Kenji Takizawa, Tayfun E. Tezduyar
Summary: Representing boundary layers and contact accurately in computational flow analysis is challenging. The space-time topology change method allows for moving-mesh computation with contact, while maintaining high-resolution flow representation near the surfaces. Using these methods, many challenges in flow analysis with complex geometries, rotating or deforming surfaces, and multiscale flows have been addressed. This two-part article provides an overview of these methods and the specific challenges encountered in tire aerodynamics.
JOURNAL OF MECHANICS
(2022)
