Yang Liu;Tianhuan Luo;Aman Rani;Hengrui Luo;Xiaoye Sherry Li
{"title":"Detecting Resonance of Radio-Frequency Cavities Using Fast Direct Integral Equation Solvers and Augmented Bayesian Optimization","authors":"Yang Liu;Tianhuan Luo;Aman Rani;Hengrui Luo;Xiaoye Sherry Li","doi":"10.1109/JMMCT.2023.3311322","DOIUrl":"https://doi.org/10.1109/JMMCT.2023.3311322","url":null,"abstract":"This article presents a computationally efficient framework for identifying resonance modes of 3D radio-frequency (RF) cavities with damping waveguide ports. The proposed framework relies on surface integral equation (IE) formulations to convert the task of resonance detection to the task of finding frequencies at which the lowest few eigenvalues of the system matrix is close to zero. For the linear eigenvalue problem with a fixed frequency, we propose leveraging fast direct solvers to efficiently invert the system matrix; for the frequency search problem, we develop a hybrid optimization algorithm that combines Bayesian optimization with down-hill simplex optimization. The proposed IE-based resonance detection framework (IERD) has been applied to detection of high-order resonance modes (HOMs) of realistic accelerator RF cavities to demonstrate its efficiency and accuracy.","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49962813","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Electro-Acoustic Scattering From a Pulsating Sphere","authors":"Viswarupa V;Yoginder Kumar Negi;N. Balakrishnan","doi":"10.1109/JMMCT.2023.3307180","DOIUrl":"https://doi.org/10.1109/JMMCT.2023.3307180","url":null,"abstract":"In this article, we show the RCS enhancement due to the acoustic disturbances around a pulsating sphere. The acoustic variation is modelled with the dielectric inhomogeneities around the sphere caused by the pressure fluctuations due to the acoustic source. RCS is computed for the modelled dielectric pulsating sphere, a cube, and a cone on a cylinder across a frequency band using Finite Difference Time Domain (FDTD) method. The RCS of the pulsating sphere and other objects considered are dominated by the background scattering from the pulsating object. In this work, we show that the dielectric variation due to the acoustic source can be detected even if there is no scattering from the object. The scattering from the dielectric variation leads to the detection of Bragg scattering along with a significant increase in RCS.","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49962812","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Christian Rümpler;Albert Zacharias;Rakesh B. Chechare;Li Yu;Carsten Dehning
{"title":"Coupling of Magneto–Hydrodynamics and Structural Models to Predict Wall Deformation due to Arcing","authors":"Christian Rümpler;Albert Zacharias;Rakesh B. Chechare;Li Yu;Carsten Dehning","doi":"10.1109/JMMCT.2023.3306154","DOIUrl":"https://doi.org/10.1109/JMMCT.2023.3306154","url":null,"abstract":"Electric arc discharges in low–voltage (LV) or medium–voltage (MV) power distribution devices can cause significant pressure rise. For example, a high amplitude pressure peak can damage the housing of a LV circuit breaker initiating cracks during short circuit interruption. In case of larger deformations or creation of additional gaps, the impact of the geometric changes on the pressure rise cannot be neglected. This article describes a new three–codes–coupling approach, wherein a magneto–hydrodynamics (MHD) model consisting of a fluid–flow solver and an electromagnetic solver are coupled with a structural dynamics solver to build a complex co–simulation model. This model can predict the deformation of structures under the influence of arcing pressure. The applicability of the model was tested with a setup, where an electric arc is ignited inside an arc chamber that has a flexible plate on one side. Predicted pressure rise and displacement results are in good agreement with test data. In a more complex setup, this approach was applied to model the bending of a flexible baffle plate in the venting path of a LV circuit breaker during short circuit interruption. Additional challenges such as contact motion and pre–stress analysis were resolved.","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49962811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Generalized Helmholtz Decomposition for Modal Analysis of Electromagnetic Problems in Inhomogeneous Media","authors":"Jie Zhu;Thomas E. Roth;Dong-Yeop Na;Weng Cho Chew","doi":"10.1109/JMMCT.2023.3305008","DOIUrl":"https://doi.org/10.1109/JMMCT.2023.3305008","url":null,"abstract":"Potential-based formulation with generalized Lorenz gauge can be used in the quantization of electromagnetic fields in inhomogeneous media. However, one often faces the redundancy of modes when finding eigenmodes from potential-based formulation. In free space, this can be explained by the connection to the well-known Helmholtz decomposition. In this work, we generalize the Helmholtz decomposition to its generalized form, echoing the use of generalized Lorenz gauge in inhomogeneous media. We formulate electromagnetics eigenvalue problems using vector potential formulation which is often used in numerical quantization. The properties of the differential operators are mathematically analyzed. Orthogonality relations between the two classes of modes are proved in both continuous and discrete space. Completeness of two sets of modes and the orthogonality relations are numerically validated in inhomogeneous anisotropic media. This work serves as a foundation for numerical quantization of electromagnetic fields in inhomogeneous media with potential-based formulation.","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49962810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Optimization Using Backtracking Search Algorithm for the Design of Magnetron Anode Block and Pill-Box RF Window","authors":"Patibandla Anilkumar;Dobbidi Pamu;Tapeshwar Tiwari","doi":"10.1109/JMMCT.2023.3304970","DOIUrl":"https://doi.org/10.1109/JMMCT.2023.3304970","url":null,"abstract":"Determining the design variables of the magnetron sub-assemblies using empirical equations is a challenge. In this article, with the help of the popular backtracking search algorithm (BSA), the bare anode block of the magnetron and pill-box RF window are designed at frequency of 2.998 GHz. The convergence results with BSA are validated with the harmony search algorithm (HSA) and particle swarm optimization (PSO). The optimized design variables of bare anode are hole radius (\u0000<inline-formula><tex-math>$a$</tex-math></inline-formula>\u0000), slot length (\u0000<inline-formula><tex-math>$l_{s}$</tex-math></inline-formula>\u0000), slot width (\u0000<inline-formula><tex-math>$W_{s}$</tex-math></inline-formula>\u0000), and anode height (\u0000<inline-formula><tex-math>$h_{a}$</tex-math></inline-formula>\u0000) which are found to be 3.1, 2.9, 12.8, and 100 mm, respectively, and converge within 150 iterations with BSA. The optimized results are compared to simulated results which are nearly identical with a negligible relative difference of \u0000<inline-formula><tex-math>$pi$</tex-math></inline-formula>\u0000-mode is 1.08%. From the pill-box RF window design, multi-objective optimization is carried out to reach the desired frequency and to achieve minimized reflections by maximizing the bandwidth. The corresponding design variables dielectric thickness (\u0000<inline-formula><tex-math>$t_{w}$</tex-math></inline-formula>\u0000), cavity length (\u0000<inline-formula><tex-math>$C_{l}$</tex-math></inline-formula>\u0000), and cavity radius (\u0000<inline-formula><tex-math>$C_{r}$</tex-math></inline-formula>\u0000) which are 2.5, 30.4, and 41.5 mm, respectively. Pareto multi-objective BSA (PMBSA) is validated with the weighted sum approach (WSA). Due to its simplicity and lower latency, optimization approach is helpful to designers to develop the microwave devices.","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49962808","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sami Barmada;Paolo Di Barba;Nunzia Fontana;Maria Evelina Mognaschi;Mauro Tucci
{"title":"Electromagnetic Field Reconstruction and Source Identification Using Conditional Variational Autoencoder and CNN","authors":"Sami Barmada;Paolo Di Barba;Nunzia Fontana;Maria Evelina Mognaschi;Mauro Tucci","doi":"10.1109/JMMCT.2023.3304709","DOIUrl":"https://doi.org/10.1109/JMMCT.2023.3304709","url":null,"abstract":"In this work, a Deep Learning approach based on a Conditional Variational Autoencoder (CVAE) and a Convolutional Neural Network (CNN) has been adopted for the solution of inverse problems and electromagnetic field reconstruction; the method is applied to the TEAM 35 benchmark magnetostatic problem. The aim of the proposed method is twofold: first, knowing the magnetic field distribution in a subdomain, the magnetic field distribution \u0000<inline-formula><tex-math>${bm{B}}$</tex-math></inline-formula>\u0000 in the whole domain is determined (field reconstruction problem). For this problem a CVAE is proposed and trained. The CVAE prediction is based on an optimization procedure in the latent space, which uses an automatic differentiation technique. Subsequently, knowing the magnetic field distribution in the whole domain, the aim is to find, using a CNN regression model, the geometrical characteristics of the source (source identification problem).","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49962809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Arman Afsari;Paulo de Souza;Amin Abbosh;Yahya Rahmat-Samii
{"title":"Lorentz-Invariant Meshless Vector Basis Function for Translational Motion of Coordinates in Computational Electromagnetics","authors":"Arman Afsari;Paulo de Souza;Amin Abbosh;Yahya Rahmat-Samii","doi":"10.1109/JMMCT.2023.3303813","DOIUrl":"https://doi.org/10.1109/JMMCT.2023.3303813","url":null,"abstract":"Laws of physics remain unchanged under translational motion of coordinates. To guarantee the above postulate in electromagnetics, Lorenz gauge eliminates the additional terms generated in the wave equation of magnetic vector potential during translational motion. When it comes to computational electromagnetics, nonetheless, Coulomb gauge is still preferred to represent the divergence of the magnetic vector potential; the vector basis functions involved in the computation of magnetic vector potential are thus divergence-free. There is, however, an immediate consequence that we shall consider here. These vector basis functions cannot incorporate any kinematic transformation of the system of coordinates. The solution achieved by them is, therefore, invalid under translational motion of the system of coordinates as a whole. Less attention has been paid to this side of computational electromagnetics, as the problems that we solve do not usually undergo any kinematic transformation. The new meshless vector basis function presented in this article is Lorentz-invariant. The solution achieved by it is, therefore, valid under translational motion. Even in local problems, the solution achieved by the newly-introduced Lorentz-invariant vector basis function demonstrates more accuracy and efficiency with respect to the solution achieved by the divergence-free vector basis functions in meshless method.","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49962914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Accurate Prediction of Measured Microwave-Induced Thermoacoustic Signals via Multiphysics Simulations Augmented With an Acoustic Detection System Transfer Function","authors":"Audrey L. Evans;Chu Ma;Susan C. Hagness","doi":"10.1109/JMMCT.2023.3303871","DOIUrl":"https://doi.org/10.1109/JMMCT.2023.3303871","url":null,"abstract":"Multiphysics simulation tools for modeling the generation and propagation of microwave-induced thermoacoustic (TA) signals aid in the development of emerging applications in medical imaging and communications. Simulation models of microwave-induced TA signals that lack consideration of the impact of the acoustic detection system result in a mismatch in the temporal characteristics of simulated and measured TA signals. We address this discrepancy by introducing an acoustic detection system transfer function that captures the combined effects of the ultrasound transducer and the acoustic signal filtering/amplification system and can be applied to simulated signals to improve their predictive accuracy. We determine the transfer function of a microwave-induced TA signal measurement system by comparing simulated and measured TA signals in a training testbed. We apply this transfer function to a set of simulated TA signals obtained from a performance evaluation testbed (differing from the training testbed) and compare to measured TA signals from that same testing scenario. We show that this technique resolves a long-standing discrepancy between simulation and experiment. Our proposed methodology for determining the acoustic detection system transfer function can be extended to other acoustic detection applications that require high-fidelity simulation models.","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49962916","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Reduced Order Modeling for Parameterized Electromagnetic Simulation Based on Tensor Decomposition","authors":"Xiao-Feng He;Liang Li;Stéphane Lanteri;Kun Li","doi":"10.1109/JMMCT.2023.3301978","DOIUrl":"https://doi.org/10.1109/JMMCT.2023.3301978","url":null,"abstract":"We present a data-driven surrogate modeling for parameterized electromagnetic simulation. This method extracts a set of reduced basis (RB) functions from full-order solutions through a two-step proper orthogonal decomposition (POD) method. A mapping from the time/parameter to the principal components of the projection coefficients, extracted by canonical polyadic decomposition (CPD), is approximated by a cubic spline interpolation (CSI) approach. The reduced-order model (ROM) is trained in the offline phase, while the RB solution of a new time/parameter value is recovered fast during the online phase. We evaluate the performance of the proposed method with numerical tests for the scattering of a plane wave by a 2-D multi-layer dielectric disk and a 3-D multi-layer dielectric sphere.","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49962915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fahimeh Sepehripour;Bastiaan P. de Hon;Martijn C. van Beurden
{"title":"Multi-Mode Analysis of Scattering by Bodies of Revolutions via the Combined-Field Integral Equation","authors":"Fahimeh Sepehripour;Bastiaan P. de Hon;Martijn C. van Beurden","doi":"10.1109/JMMCT.2023.3297926","DOIUrl":"https://doi.org/10.1109/JMMCT.2023.3297926","url":null,"abstract":"The numerical simulation of electromagnetic scattering by PEC bodies of revolution (BORs) involves computing the modal Green functions (MGFs) arising in the electric field integral equation (EFIE) and magnetic field integral equation (EFIE) for a large number of modes. We achieve this by employing five-term recurrence relations that enable the accurate and efficient computation of the MGFs for a large sequence of modes. The computation time of the five-term recurrence relations is decreased by proper truncation of the associated infinite-dimensional matrix representations. The EFIE and MFIE are then employed together in the combined-field integral equation (CFIE), which overcomes the interior resonance problem that occurs in the electromagnetic scattering by PEC BORs with closed geometries. The performance of the proposed technique is validated by analyzing the scattering of modest to large-size PEC bodies of revolution.","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49981548","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}