Purpose The onset of Darcy–Benard convection in a fluid-saturated porous layer within channeled walls can be through either the convectively amplified perturbations or absolutely unstable modes. The convective type route to formation of cellular forms has received much more interest in the literature than the absolute mode. This paper aims to explore the absolute instability mechanism on triggering

Purpose The purpose of this study is to model steam condensing flows through steam turbine blades and find the most suitable condensation model to predict the condensation phenomenon. Design/methodology/approach To find the most suitable condensation model, five nucleation equations and four droplet growth equations are combined, and 20 cases are considered for modelling the wet steam flow through

Purpose This paper aims to reconstruct the spatially varying orthotropic conductivity based on a two-dimensional inverse heat conduction problem described by a partial differential equation (PDE) model with mixed boundary conditions. The proposed discretization uses a highly accurate technique and allows simple implementations. Also, the authors solve the related inverse problem in such a way that

Purpose This paper aims to study the impact of convexity and concavity of the vertical borders on double-diffusive mixed convection. In addition, the study of entropy generation is performed. This numerical study has been carried out for different patterns of wavy edges to reveal their effects on heat and mass transfer phenomena. Design/methodology/approach Four different flow features are treated

Purpose The purpose of this study is to investigate the reflection of plane waves in a double-porosity (DP) thermoelastic medium. Design/methodology/approach To derive the theoretical formulas for elastic wave propagation velocities through the potential decomposition of wave-governing equations. The boundary conditions have been designed to incorporate the unique characteristics of the surface pores

Purpose This paper aims to present an unconditionally energy-stable scheme for approximating the convective heat transfer equation. Design/methodology/approach The scheme stems from the generalized positive auxiliary variable (gPAV) idea and exploits a special treatment for the convection term. The original convection term is replaced by its linear approximation plus a correction term, which is under

Purpose This numerical study aims to investigate the modification of the hexagonal pin fin geometry to enhance both the thermal and hydraulic performance of the copper micropin fin heat sink with single-phase water coolant in a laminar regime. The heat sink performance evaluation criteria have been investigated for the parametric effects of vertex angle θ (10–120) and relative length (RL) (0.25–9)

Abstract not available

Abstract not available

Purpose The purpose of this paper is to study the dynamical properties of a rotating rigid body (RB) containing a viscous incompressible fluid. Design/methodology/approach The Reynolds number is assumed to be small so that the governing equations can be easily obtained, and the asymptotic technique is used to solve the problem. Findings The effects of the various body parameter values on the motion’s

Purpose The transpiration has been recognized as one of the most effective thermal protection methods for future hypersonic vehicles. To improve efficiency and safety, it is urgent to optimize the design of the transpiration system for heat and drag reduction. The purpose of this paper is to investigate the effects of transpiration on heat and drag reduction. Design/methodology/approach A chemical

Purpose This paper aims to introduce a new numerical approach based on the local weak form and the Petrov–Galerkin idea to numerically simulation of a predator–prey system with two-species, two chemicals and an additional chemotactic influence. Design/methodology/approach In the first proceeding, the space derivatives are discretized by using the direct meshless local Petrov–Galerkin method. This generates

The propagations of acoustic waves in bubbly liquids have been extensively investigated through experimental and theoretical methods, a computational fluid dynamics (CFD) method was introduced to investigate the acoustic attenuation through bubbles in this study. Numerical ‘measurements’ of attenuation coefficient (α) and phase velocity (V) were conducted using a homogeneous cavitation model, which

ABSTRACT In tsunami inundations or slope disasters of heavy rain, a lot of floating debris or driftwood logs are included in the flows. The damage to structures from solid body impacts is more severe than the damage from the water pressure. In order to study free-surface flows that include floating debris, developing a high-accurate simulation code of free-surface flows with high performance for large-scale

Purpose The purpose of this study is to investigate the errors arising from the numerical treatment of model processes, paying particular attention to the impact of key system features including widely variable dispersion coefficients, spatiotemporal velocities of algal cells, and the aggregation of algae from single cells to large colonies. An advection–dispersion model has been presented to describe

To create a highly efficient photovoltaic-thermal (PV-T) system and maximise the energy and exergy efficiency, this study aims to propose an innovative configuration of a PV-T system comprising wavy tubes with twisted-tape inserts. Following the validation of a numerical model, a parametric study has been conducted to assess the geometrical effects of twisted tape and wavy tubes, as well as the coolant

Purpose This paper aims to investigate the impact of three different flow channel cross sections on the performance of the fuel cell. Design/methodology/approach A comprehensive three-dimensional polymer electrolyte membrane fuel cell model has been developed, and a set of conservation equations has been solved. The flow is assumed to be steady, fully developed, laminar and isothermal. The investigated

Compressible flow through a branched duct and the motion of a sphere through a high blockage ratio pipe are two important and engaging topics throughout the years. The results of studies on these topics are of practical relevance to many fields such as the gas pipeline technology, air transport systems in gas turbines technology, and tube transportation, etc. However, studies on the motion of a sphere

Purpose The purpose of this paper is to find approximate solutions for a general class of fractional order boundary value problems that arise in engineering applications. Design/methodology/approach A newly developed semi-analytical scheme will be applied to find approximate solutions for fractional order boundary value problems. The technique is regarded as an extension of the well-established variation

Purpose Ventilation of indoor spaces is required for the delivery of fresh air rich in oxygen and the removal of carbon dioxide, pollutants and other hazardous substances. The COVID-19 pandemic brought the topic of ventilating crowded indoors to the front line of health concerns. This study developed a new biologically inspired concept of biomimetic active ventilation (BAV) for interior environments

Purpose The purpose of this paper is to reveal the solute segregation behavior in the molten and solidified regions during direct chill (DC) casting of a large-size magnesium alloy slab under no magnetic field (NMF), harmonic magnetic field (HMF), pulsed magnetic field (PMF) and two types of out-of-phase pulsed magnetic field (OPMF). Design/methodology/approach A 3-D multiphysical coupling mathematical

Purpose This paper aims to improve Reynolds-averaged Navier Stokes (RANS) turbulence models using a data-driven approach based on machine learning (ML). A special focus is put on determining the optimal input features used for the ML model. Design/methodology/approach The field inversion and machine learning (FIML) approach is applied to the negative Spalart-Allmaras turbulence model for transonic

Purpose This paper aims to propose a dedicated measurement methodology able to simultaneously determine the stability derivative Cmα̇ and the pitch damping coefficient sum Cmq + Cmα̇ in a wind tunnel using a single and almost non-intrusive metrological setup called MiRo. Design/methodology/approach To assess the MiRo method’s reliability, repeatability and accuracy, the measurements obtained with this