In the present study, the effect of free surface on the hydrodynamic forces acting on the motion of an autonomous underwater vehicle (AUV) has been investigated. The AUV is powered by solar energy. Using computational fluid dynamics, the Reynolds averaged Navier Stokes (RANS) equations for the flow around the AUV are solved, and the free surface effect is simulated using the volume of fluid (VOF) two-phase flow model. For this purpose, the commercial code ANSYS...
A quadrature-free Legendre polynomial approach for the fast modelling guided circumferential wave in anisotropic fractional order viscoelastic hollow cylindersX. Zhang, S. Liang, S. Shao & J. Yu
Compared to the traditional integer order viscoelastic model, a fractional order derivative viscoelastic model is shown to be advantageous. The characteristics of guided circumferential waves in an anisotropic fractional order Kelvin–Voigt viscoelastic hollow cylinder are investigated by a quadrature-free Legendre polynomial approach combining the Weyl definition of fractional order derivatives. The presented approach can obtain dispersion solutions in a stable manner from an eigenvalue/eigenvector problem for the calculation of wavenumbers and displacement profiles of viscoelastic...
The presented paper is concerned with the propagation of Rayleigh waves in an orthotropic nonlocal micropolar elastic half-space. The main aim of the paper is to derive dispersion equations of Rayleigh wave as well as Stroh formalism for the orthotropic nonlocal micropolar medium. Based on the obtained dispersion equation, the effect of material, nonlocality parameter on the Rayleigh wave propagation is considered through some numerical examples.
The paper presents the local linear stability analysis of the double annular jets. The calculations show that the first absolutely unstable helical mode can be generated in the non-swirling annular jets by the back-flow in the central recirculation zone or sufficiently strong back-flow in the external recirculation zone. The influence of the back-flow magnitude on the frequency, growth rate and eigenfunctions of the first helical mode is discussed. The calculations are completed with an analysis...
Nonlinear Vibration of Multi-Walled Carbon Nanotubes with Initial Curvature Resting on Elastic Foundations in a Nonlinear Thermo-Magnetic EnvironmentGbeminiyi Musibau SOBAMOWO, James A. AKANMU, Olurotimi A. ADELEYE, Samuel AKINGBADE & Ahmed Amao YINUSA
The present work focuses on nonlinear dynamics models of multi-walled carbon nanotubes with initial curvature resting on Winkler-Pasternak elastic foundations in a nonlinear thermomagnetic environment using nonlocal elasticity theory. The derived systems of nonlinear vibration models are solved with the aid of the Galerkin decomposition and the homotopy perturbation method. Effects of temperature, magnetic field, multi-layer, and other thermomechanical parameters on the dynamic responses of the slightly curved multi-walled carbon nanotubes are investigated and discussed....
Solidification cracking is a critical phenomenon, especially in the welding of AA6XXX, due these alloys present a wider freezing temperature range. The amount of liquid at the end of the solidification is a dominant factor in promoting or reducing the number of cracks. This paper proposes to assess the effect of the heat input in controlling the cracking during the spot welding in AA6061-T6. Four deposit conditions, made with GTAW, were assessed, in which the...
Numerical investigation on the nanofluids heat transfer inside a porous inclined cavity with wavy boundaryB. Karimi, M. Pirmohammadi & A. Salehi-Shabestari
In the present work, a numerical study on the free-convective heat transfer in a porous media cavity with a wavy boundary was carried out. The validation was done by comparing the results with the experimental data. The cavity inclination angle, material of nanofluid, nanoparticles volume fraction, the Rayleigh number, and porosity of the medium are the parameters which are investigated in this study. Results suggested that, due to the thermophysical properties of Cu particles in...
We investigate the upper bound on the vertical heat transport in the fully 3D Rayleigh–Bénard convection problem at the infinite Prandtl number for a micropolar fluid. We obtain a bound, given by the cube root of the Rayleigh number, with a logarithmic correction. The derived bound is compared with the optimal known one for the Newtonian fluid. It follows that the (optimal) upper bound for the micropolar fluid is less than the corresponding bound for...
Flange connections can commonly be seen in advertising board structures, which are subjected to wind loading. Depending on the structure’s geometry, additional torsion forces should be taken into account. In this paper the static behaviour of a flange connection with highstrength bolts under torsion load has been discussed. The numerical analysis concerns two cases: a flange connection subjected only to a high-strength bolts prestressing load and a flange connection subjected to both – bolts prestressing...
The paper deals with an original methodology for modelling and control system design of the semi-active and active systems. At first a generalised simulation model of the vibration reduction system is formulated in such a way that it represents the dynamics of human body exposed to mechanical vibration. Then a novel control system design is proposed in order to adjust force characteristics of the fundamental elements included in the suspension system and consequently to reduce...
The experimental study of shock wave compressibility and spall strength of an aramid fiber reinforced epoxy composite (textolite) for two fiber orientations was performed by the VISAR interferometer. The particle velocity profiles were obtained at velocities of the flyer plate from 0.65 to 5.05 km/s. The sound speed of textolite for the longitudinal direction is three times higher than that for transverse one, and as a result, the particle velocity profiles are different for two...
Poznań University of Technology7
Częstochowa University of Technology4
Military University Nueva Granada3
Phetchabun Rajabhat University2
AGH University of Science and Technology2
Cracow University of Technology2
Vellore Institute of Technology University2
University of Alberta2