1102 On the Growth of Oblique T-S waves in Laminar Flow Region around a Turbulence Wedge Induced by Jet Injection(2)

2006 ◽  
Vol 2006 (0) ◽  
pp. _1102-1_-_1102-4_
Author(s):  
Tsuneo AZUMA ◽  
Kensuke MARUYAMA ◽  
Yusuke YAMAMOTO ◽  
Hiroki INATANI
Keyword(s):  
Laminar Flow ◽  
Flow Region ◽  
Jet Injection ◽  
S Waves

1102 On the Growth of Oblique T-S waves in Laminar Flow Region around a Turbulence Wedge Induced by Jet Injection(1)

2006 ◽  
Vol 2006 (0) ◽  
pp. _1102-a_
Author(s):  
Tsuneo AZUMA ◽  
Kensuke MARUYAMA ◽  
Yusuke YAMAMOTO ◽  
Hiroki INATANI
Keyword(s):  
Laminar Flow ◽  
Flow Region ◽  
Jet Injection ◽  
S Waves

scholarly journals Laminar Mixing in Stirred Tank Agitated by an Impeller Inclined

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Koji Takahashi ◽  
Yoshiharu Sugo ◽  
Yasuyuki Takahata ◽  
Hitoshi Sekine ◽  
Masayuki Nakamura
Keyword(s):  
Numerical Simulation ◽  
Laminar Flow ◽  
Mixing Time ◽  
Flow Region ◽  
Experimental Results ◽  
Stirred Tank ◽  
Simulation Methods ◽  
Mixing Performance ◽  
Laminar Mixing ◽  
Numerical Simulation Methods

The mixing performance in a vessel agitated by an impeller that inclined itself, which is considered one of the typical ways to promote mixing performance by the spatial chaotic mixing, has been investigated experimentally and numerically. The mixing time was measured by the decolorization method and it was found that the inclined impeller could reduce mixing time compared to that obtained by the vertically located impeller in laminar flow region. The effect of eccentric position of inclined impeller on mixing time was also studied and a significant reduction of mixing time was observed. To confirm the experimental results, the velocity profiles were calculated numerically and two novel numerical simulation methods were proposed.

CFD Study of Pitch Variations On Helically Coiled Pipe in Laminar Flow Region

2020 ◽  
Author(s):  
Anwer Faraj ◽  
Itimad D J Azzawi ◽  
Samir Ghazi Yahya ◽  
Amer Al-damook
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Laminar Flow ◽  
Friction Factor ◽  
Flow Structure ◽  
Flow Region ◽  
Alternative Solution ◽  
Experimental Investigations ◽  
Coil Diameter ◽  
Computational Fluid Dynamics Cfd

Abstract Experimental investigations of the flows inside helically coiled pipe are difficult and may also be expensive, particularly for small diameters. Computational fluid dynamics (CFD) packages, which can easily construct the geometry and change the dimensions with 100% of accuracy, provide an alternative solution for the experimental difficulties and uncertainties. Therefore, a computational fluid dynamics (CFD) study was conducted to analyse the flow structure and the effect of varying the coil pitch on the coil friction factor, through utilising different models' configurations. Two coils were tested, all of them sharing the same pipe and coil diameter: 0.005m and 0.04m respectively. Pitch variations began with 0.01 and 0.05 m for the first, second model respectively. In this study, the velocity was analysed, and the effects of this reduction on coil friction factor were also examined using laminar flow. The results were validated by Ito's equation for the laminar flow.

Measurement of Laminar Flow Development in a Square Duct Using a Laser-Doppler Flowmeter

1967 ◽  
Vol 34 (4) ◽  
pp. 813-818 ◽  
Author(s):  
R. J. Goldstein ◽  
D. K. Kreid
Keyword(s):  
Laminar Flow ◽  
Precision Measurement ◽  
Fluid Velocity ◽  
Flow Distribution ◽  
Flow Region ◽  
Optical Technique ◽  
Fully Developed Flow ◽  
Square Duct ◽  
Flow Development ◽  
Doppler Flowmeter

A system for precision measurement of fluid velocity is developed and applied to determine the laminar flow distribution in a square duct. The experimental technique consists of measuring the Doppler shift of laser radiation scattered by particles moving with the fluid. From this frequency shift, the fluid velocity is inferred. Measurements in the entrance region and fully developed flow region of a square duct indicate that the velocity profile development takes place in a somewhat longer section of the duct than had been predicted. Measurements of the fully developed flow indicate that the optical technique used is capable of measuring velocity within an accuracy of at least 0.1 percent.

scholarly journals Predicting the Pressure Drop of Corrugated Sheet Structured Packings in Deep Vacuum Applications

2019 ◽  
Vol 33 (3) ◽  
pp. 303-323
Author(s):  
Žarko Olujić
Keyword(s):  
Pressure Drop ◽  
Laminar Flow ◽  
Flow Region ◽  
Packed Bed ◽  
Internal Diameter ◽  
Flow Conditions ◽  
Natural Choice ◽  
Total Reflux ◽  
Wire Gauze ◽  
Structured Packings

Advanced corrugated sheet structured packings are considered a natural choice for<br /> deep vacuum distillation. In many of these applications that occur at absolute pressures<br /> below 0.01 bar at the top of the column, the low density gas/vapor driven by pressure<br /> ascends through an irrigated packed bed under laminar flow conditions. This implies that the packing geometry features aiming to reduce the form drag of advanced packing may not be as effective, if at all, as experienced in common applications where turbulent flow prevails. To consider this appropriately, a theoretically founded expression for laminar flow friction factor has been incorporated into Delft model (DM). With this extension, the predicted pressure drop within laminar flow region approaches closely that estimated using well-established empirical model available in software package SULCOL. In absence of adequate experimental evidence, extended DM was validated using newest data obtained at FRI with an advanced wire gauze structured packing in total reflux experiments carried out with paraxylene/orthoxylene system at 0.02 and 0.1 bar top pressure in a column with internal diameter of 1.22 m.

Steady expiratory flow in dog lungs: an isovolume preparation

1981 ◽  
Vol 51 (5) ◽  
pp. 1331-1337 ◽  
Author(s):  
S. L. Sneddon ◽  
J. D. Brain
Keyword(s):  
Reynolds Number ◽  
Pressure Drop ◽  
Laminar Flow ◽  
Flow Region ◽  
Flow Limitation ◽  
Opening Pressure ◽  
Pressure Flow ◽  
Pleural Surface ◽  
Airway Opening ◽  
Expiratory Flow

By supplying air and other gases through discs glued to the pleural surface, we studied steady expiratory flow at constant volume. Dog lungs were studied at constant PA - Ppl (alveolar minus pleural pressure) of 7 to 10 cmH2O, as increasing flow was achieved by increasing driving pressure [Ppl - Pao (airway opening pressure)]. Flow became limited (independent of further increases in Ppl - Pao) at between 3.5 and 5.5 l/s. Isovolume-pressure-flow (IVPF) curves constructed from forced expirations at graded efforts yielded similar maximal flows. When the airways were made rigid by drying, flow limitation was abolished. When various gases were passed through the dried lung Moody plots of normalized pressure drop (CD) vs. Reynolds number (Re) showed that all of the data could be plotted on a single curve. Although variable among animals, all Moody plots showed a laminar flow region at Re below 100 and an inertial region at Re above 10,000, with a distinct transition.

Experimental Study on Thermal-Hydraulic Performance of Single-Phase Water Flow in Narrow Rectangular Channel

2009 ◽  
Author(s):  
Mei Wang ◽  
Yan Wen ◽  
Suizheng Qiu ◽  
Guanghui Su ◽  
Weifeng Ni
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Nusselt Number ◽  
Laminar Flow ◽  
Friction Factor ◽  
Water Flow ◽  
Single Phase ◽  
Rectangular Channel ◽  
Flow Region ◽  
Phase Water

The purpose of this study is to discover the differences of pressure drop and heat transfer of single-phase water flow between conventional channels and narrow rectangular channels. Furthermore, the differences between the level and the vertical channel have been studied. The gap of the test channel is 1.8mm. Compared with conventional channels, the narrow rectangular channel showed differences in both flow and heat transfer characteristics. The critical Reynolds number of transition from laminar flow to turbulent flow is 900∼1300, which is smaller compared with conventional channels. The friction factor is larger than that of the conventional channels and the correlation of friction factor with Reynolds number was given by experimental results. From the relation graph of Nusselt number and Reynolds number, the demarcation of the laminar flow region and turbulence flow region is obvious. In laminar region, Nusselt number almost remained constant and approximately consistent with numerical simulation results. While in turbulent region, Nusselt number increased significantly with increasing Reynolds number. A new Nusselt number correlation was obtained based on Dittus-Boelter equation, and the coefficients were less about 13% than that of Dittus-Boelter equation.

scholarly journals Combined Electrochemical & Biological Treatment of Industrial Wastewater Using Porous Electrodes and a Packed Bed Aerator

2021 ◽  
Author(s):  
Robert Mitzakov
Keyword(s):  
Laminar Flow ◽  
Electrochemical Cell ◽  
Flow Region ◽  
Packed Bed ◽  
Electrochemical Treatment ◽  
Porous Electrodes ◽  
Turbulent Region ◽  
Porous Aluminum ◽  
Liquid Flux ◽  
Laminar And Turbulent Flow

Zinc, nickel and propylene glycol methyl ether were simultaneously removed from simulated wastewater in a column containing a counter-current packed bed and an electrochemical cell. Rectangular porous aluminum foam cathode and porous stainless steel anode were used in a plate-in-tank configuration. During combined biological and electrochemical treatment the wastewater flux was 0.00183 and 0.00915 m³.m̈².s̈¹ at a constant volumetric air flux of 0.0518 m³.m̈².s̈¹. Over a 72 hour treatment period the BOD5 was reduced by 32% and 55% for each volumetric liquid flux, respectively; zinc was reduced by 98% for both fluxes, and nickel was reduced by 95% and 82%, respectively. For sole electrochemical treatment of 48 hours, laminar and turbulent flow conditions were studied. Operating in the laminar flow region of 0.00183 and 0.00915 m³.m̈².s̈¹; zinc was reduced by 95% for both fluxes; nickel was reduced by 80% and 60%, respectively. For the turbulent region in the electrochemical cell, the volumetric liquid fluxes were 0.0137, 0.0229, 0.0321 and 0.0366 m³.m̈².s̈¹. Per cent reduction of both zinc and nickel in this region was less than that encountered in laminar flow. For all the fluxes in the turbulent region zinc was reduced by 82%; nickel was reduced by 55% at a flux of 0.0137 m³.m̈².s̈¹ and 60% at a flux of 0.0366 m³.m̈².s̈¹. Increasing electrode surface area as a means of improving heavy metal reduction by using rectangular porous material in a plate-in-tank configuration is not a viable option at higher volumetric liquid fluxes.

Water slip flow in superhydrophobic microtubes within laminar flow region

2015 ◽  
Vol 23 (5) ◽  
pp. 763-768 ◽  
Author(s):  
Zhijia Yu ◽  
Xinghua Liu ◽  
Guozhu Kuang
Keyword(s):  
Laminar Flow ◽  
Slip Flow ◽  
Flow Region
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