This paper presents the experimental study of pressure and velocity fluctuations and their interdependence, in the turbulent flow impinging on arrangements of yawed circular cylinders simulating inclined tube banks with square arrangement and a pitch to diameter ratio of 1.26. Measurements were performed with hot-wires and a pressure transducer. Behaviour of fluctuating quantities is described ...

We present a new vortex solution made of a domain wall compactified into a cylinder and stabilized by the magnetic flux within. When the thickness of the wall is much less than the radius of the vortex some precise results can be obtained, such as the tension spectrum and profile functions. This vortex can naturally end on the wall that has created it, making the simplest junction between a wal...

Flow visualisation using tracer and particle techniques is well known to be susceptible to fallacious interpretation for unsteady shear flows. Recent experimental observations using these types of techniques have led to the conclusion that even for low Reynolds number flows, the vortex breakdown bubble in a torsionally driven cylinder is not closed and has an inflow/outflow asymmetry at its tai...

in this study, selenium was recovered from an industrial dust. after the purification process, the researchers were able to prepare selenium micro powder. the objective of this study was to prepare selenium nano particles by water solution phase method from the micro powders. the results showed that selenium micronized powder and nano particles had high purity. the obtained nanoparticles were t...

The combustion characteristics of methane/moist air in micro-tube reactors with different numbers and shapes of inner wall protuberances are investigated in this paper. The micro-reactor with one rectangular protuberance (six different sizes) was studied firstly, and it is shown that reactions near the protuberance are mainly controlled by diffusion, which has little effect on the outlet temper...

An oil tube defect detection method based on self-adaptive genetic fuzzy neural network is proposed, and it got the original information by multi-group vortex sensors and leakage magnetic sensors. We made multi-scale wavelet transform and frequency analysis to multi-channels original data and extracted multiattribute parameters from time domain and frequency domain, and then we selected the key...

The direct coupling of in-tube solid-phase microextraction (in-tube SPME) with microcolumn liquid chromatography (micro-LC) has been investigated for the analysis of antidepressants in human urine. The use of in-tube SPME has been clearly shown to be advantageous for the on-line coupling of the SPME method, as the sample pretreatment technique, with micro-LC as the separation technique. This is...

Creation of patterns and structures on surfaces at the micro- and nano-scale is a field of growing interest. Direct femtosecond laser surface structuring with a Gaussian-like beam intensity profile has already distinguished itself as a versatile method to fabricate surface structures on metals and semiconductors. Here we present an approach for direct femtosecond laser surface structuring based...

For understanding the structure of an MHD-scale Kelvin-Helmholtz Instability (KHI) in a non-linear stage, we have performed two-dimensional two-fluid simulations including finite electron inertial effects. In the twofluid system, magnetic reconnection occurs spontaneously because the ’frozen-in’ condition can be broken by the electron inertial effects. When an MHD-scale velocity shear exists, a...

The instability mechanisms and mixing enhancement arising from the interaction of a compressible vortex ring with a normal shock wave were studied in a colinear, dual-shock tube. This flow geometry simulates features of the interaction of a shock wave with a jet containing streamwise vorticity, a configuration of significant interest for supersonic combustion applications. Flow visualization an...