scholarly journals Numerical Simulations of Two-Stage Ignition of Fine Single Fuel Droplets in a Closed Constant-Volume Cell

2006 ◽  
Vol 72 (713) ◽  
pp. 150-155
Author(s):  
Osamu MORIUE ◽  
Masato MIKAMI ◽  
Naoya KOJIMA ◽  
Eiichi MURASE
Keyword(s):  
Numerical Simulations ◽  
Constant Volume ◽  
Two Stage ◽  
Fuel Droplets ◽  
Volume Cell

scholarly journals Innovation and product market concentration: Schumpeter, arrow, and the inverted U-shape curve

2020 ◽  
Author(s):  
Flavio Delbono ◽  
Luca Lambertini
Keyword(s):  
Numerical Simulations ◽  
Empirical Research ◽  
Product Market ◽  
Market Concentration ◽  
Relative Strength ◽  
Stage Model ◽  
Two Stage ◽  
Shape Curve ◽  
The Relationship ◽  
Theoretical Results

Abstract We investigate the relationship between market concentration and industry innovative effort within a familiar two-stage model of R&D race in which firms compete à la Cournot in the product market. With the help of numerical simulations, we show that such a setting is rich enough to generate Arrovian, Schumpeterian, and inverted U curves. We interpret these different patterns on the basis of the relative strength of the technological incentive and the strategic incentive. We then bridge our theoretical results and some recent empirical research.

scholarly journals Soot Investigation on Fish Oil Spray Combustion in a Constant Volume Cell

2015 ◽  
Vol 8 (3) ◽  
pp. 581-596
Author(s):  
Maximilian Malin ◽  
Vladimir Krivopolianskii ◽  
Bjørn Rygh ◽  
Vilmar Aesoy ◽  
Eilif Pedersen
Keyword(s):  
Fish Oil ◽  
Constant Volume ◽  
Spray Combustion ◽  
Volume Cell

scholarly journals Two-stage Lagrangian modeling of ignition processes in ignition quality tester and constant volume combustion chambers

Fuel ◽  
2016 ◽  
Vol 185 ◽  
pp. 589-598 ◽  
Author(s):  
Adamu Alfazazi ◽  
Olawole Abiola Kuti ◽  
Nimal Naser ◽  
Suk Ho Chung ◽  
S. Mani Sarathy
Keyword(s):  
Constant Volume ◽  
Combustion Chambers ◽  
Two Stage ◽  
Lagrangian Modeling ◽  
Constant Volume Combustion ◽  
Ignition Quality ◽  
Ignition Quality Tester

scholarly journals NUMERICAL AND EXPERIMENTAL STUDY OF A TWO-STAGE SAVONIUS WIND TURBINE

2019 ◽  
Vol 18 (2) ◽  
pp. 52
Author(s):  
L. B. Kothe ◽  
A. P. Petry
Keyword(s):  
Experimental Study ◽  
Numerical Simulations ◽  
Wind Turbine ◽  
Vertical Axis ◽  
Relative Difference ◽  
Performance Comparison ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine ◽  
Two Stage ◽  
Index Method

This article presents a numerical and experimental study of vertical axis wind turbine performance comparison involving a two-stage Savonius rotor with similar parameters. The experimental study is conducted in the aerodynamic tunnel at the Fluid Mechanics Laboratory of the Federal University of Rio Grande do Sul. The aerodynamics rotors are manufactured by 3D prototyping technique. Numerical simulations are performed using the Finite Volumes Method performed by the solution of the Reynolds Averaged Navier-Stokes (RANS) and continuity equations using the SST k-ω turbulence model. The numerical domain is modeled in order to maintain the same characteristics of the experimental model. The mesh quality is evaluated through the GCI (Grid Convergence Index) method. The static and dynamic torque coefficients and the power coefficients are compared. The tests are made without blockage corrections due to the small blockage ratio from 7.5%. Results show that the turbine has a positive static torque coefficient for any rotor angles. The dynamic torque reaches the maximum value for a tip speed ratio (λ) of 0.2 for the experimental and numerical cases. The relative difference between the numerical simulations and the experimental results are between 3.8% and 13.4%.

Dense shearing flows of soft, frictional cylinders

Soft Matter ◽  
2021 ◽  
Author(s):  
Diego Berzi ◽  
Kevin E Buettner ◽  
Jennifer Sinclair Curtis
Keyword(s):  
Numerical Simulations ◽  
Constant Volume ◽  
Preferential Alignment

We perform discrete numerical simulations at constant volume of dense, steady, homogeneous flows of true cylinders interacting via Hertzian contacts, with and without friction, in the absence of preferential alignment....

Effect of Oil Viscosity on Self-Excited Noise Production Inside the Pilot Stage of a Two-Stage Electrohydraulic Servovalve

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Meng Chen ◽  
Nay Zar Aung ◽  
Songjing Li ◽  
Changfang Zou
Keyword(s):  
Numerical Simulations ◽  
Pressure Pulsation ◽  
Acoustic Resonance ◽  
Critical Issue ◽  
Small Scale ◽  
Pressure Pulsations ◽  
Oil Viscosity ◽  
Two Stage ◽  
Noise Characteristics ◽  
Noise Production

The occurrence of self-excited noise felt as squealing noise is a critical issue for an electrohydraulic servovalve that is an essential part of the hydraulic servocontrol system. Aiming to highlight the root causes of the self-excited noise, the effect of oil viscosity on the noise production inside a two-stage servovalve is investigated in this paper. The pressure pulsations' characteristics and noise characteristics are studied at three different oil viscosities experimentally by focusing on the flapper-nozzle pilot stage of a two-stage servovalve. The cavitation-induced and vortex-induced pressure pulsations' characteristics at upstream and downstream of the turbulent jet flow path are extracted and analyzed numerically by comparing with the experimental measured pressure pulsations and noise characteristics. The numerical simulations of transient cavitation shedding phenomenon are also validated by the experimental cavitation observations at different oil viscosities. Both numerical simulations and experimental cavitation observations explain that cavitation shedding phenomenon is intensified with the decreasing of oil viscosity. The small-scale vortex propagation with the characteristic of generating, growing, moving, and merging is numerically simulated. Thus, this study reveals that the oil viscosity affects the transient distribution of cavitation and small-scale vortex, which, in turn, enhances the pressure pulsation and noise. The noise characteristics achieve a good agreement with pressure pulsation characteristics showing that the squealing noise appears accompanied by the flow field resonance in the flapper-nozzle. The flow-acoustic resonance and resulting squealing noise possibly occurs when the amplitude of the pressure pulsations near the flapper is large enough inside a two-stage servovalve.

Reliability of Multiple-Stage Cascaded Passive Optical Networks: A Perspective

2014 ◽  
Vol 701-702 ◽  
pp. 994-999
Author(s):  
Ge Jun Gao ◽  
Xun Jie Li ◽  
Shuai Tao ◽  
Jian Hua Shen
Keyword(s):  
Theoretical Analysis ◽  
Numerical Simulations ◽  
Optical Networks ◽  
Optical Network ◽  
Single Stage ◽  
Passive Optical Network ◽  
Passive Optical Networks ◽  
Broadband Access ◽  
Two Stage

Passive Optical Network (PON) technology has been widely accepted as main broadband access which can satisfy the rapid increasing bandwidth requirements. With the expansion of the number of users, as well as the variation of application scenarios, traditional single-stage cascaded or two-stage cascaded PON system can no longer meet users’ demands. This paper proposed four multiple-stage cascaded PON topologies with different protection schemes. Reliability and cost for each topology are presented with theoretical analysis and numerical simulations.

An Analytical Solution to Dujmovic’s Iterative OWA

2016 ◽  
Vol 24 (Suppl. 2) ◽  
pp. 165-179 ◽  
Author(s):  
Luigi Troiano ◽  
Irene Díaz
Keyword(s):  
Analytical Solution ◽  
Theoretical Result ◽  
Numerical Simulations ◽  
Owa Operator ◽  
Two Stage ◽  
Nested Iteration ◽  
Weighting Vector ◽  
Matrix Power ◽  
Computational Solution

Iterative OWA (ItOWA) as proposed by Dujmovic, is a two-stage procedure for computing the weighting vector by a double nested iteration: (i) weights at step h are computed as limit to infinity of a matrix power, (ii) the result is used to start the computation at step h + 1, until the OWA operator arity n is reached. Thereafter Dujmovic suggested a computational solution based on the conjecture that the limit exists, and numerical simulations have being supported the hypothesis that the conjecture is correct. In this paper, we prove that the limit actually exists and we provide an analytical solution to the procedure, so the weighting vector can be computed directly instead of an iterative time-consuming procedure. This theoretical result enables a faster computation of the weighting vector and characterization in terms of weights values, attitudinal character and entropy.

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