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This paper aims to point out the critical problems in numerical verification of solidification simulation codes and the complexity of the verification and to propose and apply a procedure of generalized verification for macrosegregation simulation.

A partial verification of a finite‐volume computational model of macrosegregation in direct chill (DC) casting of binary aluminum alloys, including the coupled transport phenomena of heat transfer, fluid flow and species transport, is performed. The verification procedure is conducted on numerical test problems, defined as subproblems with respect to the complexity of the physical model, geometry, and boundary conditions. The studied cases are thermal convection with solidification in DC casting, thermal natural convection of a low‐Prandtl‐number liquid metal in a rectangular cavity and 1D directional solidification of a binary Al‐Cu alloy. Grid‐convergence studies, code comparison with an alternative Chebyshev‐collocation method, and comparison with a reference similarity solution are used for verification.

An excellent ability of the model to accurately resolve the thermal convection in the pertinent range of Prandtl and Rayleigh numbers is shown. Concerns regarding the solution of species transport in the mushy zone remain.

The proposed verification procedure is not completed in its entirety. Further verification of the solutal and thermosolutal convection problems is required.

This paper proposes verification techniques for complex coupled solidification problems involving significant convection in the melt.

The purpose of this paper is to describe the approach for the design of a jet engine composite air inlet for a new generation of jet trainer aircraft from the perspective of airworthiness requirements regarding high-speed impact resistance.

Validated numerical simulation was applied to flat test panels. The final design was optimised and verified by validated numerical simulation and verified by testing on a full-scale demonstrator. High-speed camera measurement and non-destructive testing (NDT) results were used for the verification of the numerical models.

The test results of flat test panels confirmed the high durability of the composite structure during inclined high-speed impact with a near-real jet inlet load boundary condition.

Owing to the sensitivity of the composite material on technology production, the results are limited by the material used and the production technology.

The application of flat test panels for the verification and tuning of numerical models allows optimised final design of the air inlet and reduces the risk of structural non-compliance during verification tests.

Numerical models were verified for simulation of the real composite structure based on high-speed camera results and NDT inspection after impact. The proposed numerical model was simplified for application in a real complex design and reduced calculation time.

The purpose of this paper is to present outcomes of efforts made over the last 20 years to extend the applicability of the Richardson extrapolation procedure to numerical predictions of multidimensional, steady and unsteady, fluid flow and heat transfer phenomena in regular and irregular calculation domains.

Pattern-preserving grid-refinement strategies are proposed for mathematically rigorous generalizations of the Richardson extrapolation procedure for numerical predictions of steady fluid flow and heat transfer, using finite volume methods and structured multidimensional Cartesian grids; and control-volume finite element methods and unstructured two-dimensional planar grids, consisting of three-node triangular elements. Mathematically sound extrapolation procedures are also proposed for numerical solutions of unsteady and boundary-layer-type problems. The applicability of such procedures to numerical solutions of problems with curved boundaries and internal interfaces, and also those based on unstructured grids of general quadrilateral, tetrahedral, or hexahedral elements, is discussed.

Applications to three demonstration problems, with discretizations in the asymptotic regime, showed the following: the apparent orders of accuracy were the same as those of the numerical methods used; and the extrapolated results, measures of error, and a grid convergence index, could be obtained in a smooth and non-oscillatory manner.

Strict or approximate pattern-preserving grid-refinement strategies are used to propose generalized Richardson extrapolation procedures for estimating grid-independent numerical solutions. Such extrapolation procedures play an indispensable role in the verification and validation techniques that are employed to assess the accuracy of numerical predictions which are used for designing, optimizing, virtual prototyping, and certification of thermofluid systems.

The purpose of this study is research and development of the magnetohydrodynamics (MHD)-vortex technology.

The main instruments of research are mathematical modeling. For mathematical modeling used numerical and analytical both methods. For verification was made small copy of facility with forming of vortex in rotating magnetic field.

The design and manufacture of the industrial unit for melting small metal waste in a gas-fired smelt furnace has been completed.

Here shows new algorithm for engineering calculation of arc induction systems with take into account longitudinal edge effect and discrete distribution of current layers. Also shows verification of numerical results. Presented new MHD-technology for forming vortex in electromagnetic field.

Direct current potential drop (DCPD) testing is a potential nondestructive testing method for quality control of the metallic foam (MF). The purpose of this paper is to develop a numerical technique for the efficient simulation of the DCPD signals of MFs with defects with boundary of complicated shapes.

The concept of multi-medium element (MME) is introduced to treat the boundary of complex-shaped defect. A classification scheme of Gauss integral points is also proposed to select the Gauss points that have to be taken into account in the integral calculation of the coefficient matrix of each MME.

MME is suitable for simulation of DCPD signals due to defects in complicated shapes. The numerical method for calculating the element matrix of the MME is efficient and accurate. The experimental results support the proposed method positively.

The code developed in this paper is suitable for the simulation of DCPD signals of MF due to a planar defect. The code for 3D defect is still under development.

The concept of MME introduced to deal with the simulation of DCPD signal due to defect with boundary of complicated shape, as well as the numerical technique for element coefficient matrix calculation. The developed method gives possible for the inversion of DCPD signals of complicated defect shape.

The purpose of this paper is to use numerical methods early in the airframe design process and access the structural performance of wing leading edge devices made of different materials and design details, under bird strike events.

Explicit finite element analysis was used to numerically model bird strike events.

Structural performance charts related to materials and general design details were drawn to explore the design space dictated by the current applicable airworthiness requirements.

This paper makes use of the current capability in the numerical tools available for structural simulations and exposes the existing limitations in the terms of material modelling, material properties and fracture simulation using continuum damage mechanics. Such results will always be in the need of fine-tuning with experimental testing, yet the tools can shed some light very early in the design process in a relative inexpensive manner, especially for design details down selection like materials to use, structural thicknesses and even design arrangements.

Bird strike simulations have been successfully used on aircraft design, mainly at the manufactured articles design validation, testing and certification. This paper presents a hypothetical early design case study of leading edge devices for appropriate material and skin thickness down selection.

The centrifugal instability mechanism of boundary layers over concave surfaces is responsible for the development of quasi-periodic, counter-rotating vortices aligned in a streamwise direction known as Görtler vortices. By distorting the boundary layer structure in both the spanwise and the wall-normal directions, Görtler vortices may modify heat transfer rates. The purpose of this study is to conduct spatial numerical simulation experiments based on a vorticity–velocity formulation of the incompressible Navier–Stokes system of equations to quantify the role of the transition in the heat transfer process.

Experiments are conducted using an in-house, parallel, message-passing code. Compact finite difference approximations and a spectral method are used to approximate spatial derivatives. A fourth-order Runge–Kutta method is adopted for time integration. The Poisson equation is solved using a geometric multigrid method.

Results show that the numerical method can capture the physics of transitional flows over concave geometries. They also show that the heat transfer rates in the late stages of the transition may be greater than those for either laminar or turbulent ones.

The numerical method can be considered as a robust alternative to investigate heat transfer properties in transitional boundary layer flows over concave surfaces.

The purpose of this paper is to analyze the mechanism of particle erosion in butterfly valve pipelines under hydraulic transportation conditions. The results will affect the sealing and safety of butterfly valve pipelines and hopefully serve as reference for the anti-erosion design of butterfly valve pipelines.

Through the discrete element method (DEM) simulation that considers the force between particles, the detached eddy simulation (DES) turbulence model based on realizable k-epsilon is used to simulate the solid-liquid two-phase flow-induced erosion condition when the butterfly valve is fully opened. The simulation is verified by building an experimental system correctness. The solid-liquid two-phase flow characteristics, particle distribution and erosion characteristics of the butterfly valve pipeline under transportation conditions are studied.

The addition of particles may enhance the high-speed area behind the valve. It first increases and then decreases with increasing particle size. With increasing particle size, the low-velocity particles change from being uniformly distributed in flow channel to first gathering in the front of the valve and, then, to gathering in lower part of it. Fluid stagnation at the left arc-shaped flange leads to the appearance of two high-speed belts in the channel. With increasing fluid velocity, high-speed belts gradually cover the entire valve surface by focusing on the upper and lower ends, resulting in the overall aggravation of erosion.

Considering the complexity of solid-liquid two-phase flow, this is the first time that the DEM method with added inter-particle forces and the DES turbulence model based on realizable k-epsilon has been used to study the flow characteristics and erosion mechanism of butterfly valves under fully open transportation conditions.

A novel framework for expedited antenna optimization with an iterative prediction-correction scheme is proposed. The methodology is comprehensively validated using three real-world antenna structures: narrow-band, dual-band and wideband, optimized under various design scenarios.

The keystone of the proposed approach is to reuse designs pre-optimized for various sets of performance specifications and to encode them into metamodels that render good initial designs, as well as an initial estimate of the antenna response sensitivities. Subsequent design refinement is realized using an iterative prediction-correction loop accommodating the discrepancies between the actual and target design specifications.

The presented framework is capable of yielding optimized antenna designs at the cost of just a few full-wave electromagnetic simulations. The practical importance of the iterative correction procedure has been corroborated by benchmarking against gradient-only refinement. It has been found that the incorporation of problem-specific knowledge into the optimization framework greatly facilitates parameter adjustment and improves its reliability.

The proposed approach can be a viable tool for antenna optimization whenever a certain number of previously obtained designs are available or the designer finds the initial effort of their gathering justifiable by intended re-use of the procedure. The future work will incorporate response features technology for improving the accuracy of the initial approximation of antenna response sensitivities.

The proposed optimization framework has been proved to be a viable tool for cost-efficient and reliable antenna optimization. To the knowledge, this approach to antenna optimization goes beyond the capabilities of available methods, especially in terms of efficient utilization of the existing knowledge, thus enabling reliable parameter tuning over broad ranges of both operating conditions and material parameters of the structure of interest.

This study aims to evaluate the effects of the downhole environment and auxiliary rubber bellows on the contact mechanical characteristics and sealing performance of rubber-bellows mechanical seals (RBMS) in electric submersible pumps (ESPs), considering the elastic support of the rubber bellows, multi-field coupling effect and actual operating conditions.

A thermal-fluid-solid multi-field coupling numerical model for RBMS in ESPs is developed using the finite element analysis and influence coefficient method. Based on the contact mechanical characteristics of RBMS, the interactions of multiple physical fields between the sealing rings and lubricating oil are accounted for to assess the liquid lubrication state and sealing performance of RBMS in ESPs.

The findings indicate the anti-leakage effects of rubber bellows, the transition of lubrication state of the sealing end face and the evolution law of sealing performance with environmental pressure, axial compression amount and contact widths of rubber bellows.

This study innovatively proposes a multi-field numerical research method to reveal the impact of the downhole environment and rubber bellows on RBMS in ESPs. These findings contribute to a more comprehensive understanding of the sealing mechanism of RBMS and optimize the sealing design for ESPs in high-pressure environments.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-10-2024-0369/