Sometimes it is thought that sharp transitions between potentially different turbulent states should be washed out by the prevailing intense fluctuations and short coherence lengths and times. Contrary to this expectation, we found a sequence of such transitions in turbulent rotating Rayleigh-Bénard convection as the rotation rate was increased. This phenomenon was observed in cylindrical sampl...

Richard J. A. M. Stevens, Herman J. H. Clercx, and Detlef Lohse Department of Science and Technology and J. M. Burgers Center for Fluid Dynamics, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands Department of Applied Mathematics, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands and Department of Physics and J. M. Burgers Centre for Fluid Dynamics, Eindh...

In rotating Rayleigh Bénard convection, Coriolis force stabilizes the conductive state, and the convective onset increases as rotation increases. The strength of the Coriolis force is represented by the dimensionless rotation rate Ω =2πfd2/ν where f is the rotation frequency. The conductive state becomes unstable to stationary convective parallel rolls as in Rayleigh Bénard convection, but over...

A validated dynamic model of a golf driver can be an invaluable asset in designing a well performing club. We present a model for simulating the golf drive that includes experimentally-measured inputs from actual golfers, and a three-dimensional (3D) flexible shaft model based on Rayleigh beam theory. The result is a computationally-efficient dynamic model that includes the “signature” of an in...

We consider an axi-symmetric flexible rotor perturbed by dissipative, conservative, and non-conservative positional forces originated at the contact with the anisotropic stator. The Campbell diagram of the unperturbed system is a mesh-like structure in the frequency-speed plane with double eigenfrequencies at the nodes. The diagram is convenient for the analysis of the traveling waves in the ro...

We consider an axi-symmetric rotor perturbed by dissipative, conservative, and non-conservative positional forces originated at the contact with the anisotropic stator. The Campbell diagram of the unperturbed system is a mesh-like structure in the frequency-speed plane with double eigenfrequencies at the nodes. The diagram is convenient for the analysis of the traveling waves in the rotating el...

In this paper is proposed a dynamic torque, rotational speed, and shaft position sensor. It built of magnetic elastomer coating directly applied over rotating shaft. The sensor used for precise measurements changes in torque it usable at high speeds, on the device based material deformation corresponding change field amplitude direction. design simple can acquire reliable readings wide range sp...

This work is meant to investigate and control the nonlinear dynamical behaviours of a asymmetric rotating shaft system. The studied system modeled as having both quadratic cubic nonlinearities excited at primary resonance. A linear proportional-derivative controller introduced eliminate suppress lateral vibrations shaft. influences different parameters on oscillatory considered are explored. ma...

Abstract: In this paper we investigate the complete integrability of the system of six coupled nonlinear ODEs, which arises in the ODE reduction of rotating stratified Boussinesq equations. We use Painlevé test to investigate the complete integrability of the system. And we conclude that the system is completely integrable only if the Rayleigh number Ra = 0. The singular solution of the system ...

The influence of rotation on turbulent convection is investigated with direct numerical simulation. The classical Rayleigh-Bénard configuration is augmented with steady rotation about the vertical axis. Correspondingly, characterization of the dynamics requires both the dimensionless Rayleigh number Ra and the Taylor number Ta. With increasing Ta the root-mean-square (rms) velocityvariations ar...