Circulation Velocity Research Articles

Как модель тройной спирали инноваций меняет борьбу с COVID-19 в Индии?

It is indeed a great misnomer to analyze the dimensions of academic capitalism with the steady rise of entrepreneurial university in line with Western educational policies. It has been a long journey in emerging underdeveloped economies has given the dream of the next superpower where entrepreneurial universities are a very recent concept of post-liberal economy, change in governmental practices and bureaucratic affairs. This has led to a stronger innovation landscape of industry-education-government nexus in building the nation. Recent years have seen the great crisis of COVID-19 pandemic which has changed the ideologies and theoretical models underlying economically well-off states and the velocity of money circulation. Amidst the huge amount of literature in entrepreneurial university studies, very little work has been done which answers the very pertinent question and covers the research gap. Namely, how the Triple Helix model arrived in India and how the central government in India dramatically changed its beliefs by inheriting such a model in its innovation practices. The model that championed the cause of bringing about new products, economic welfare and product development. These transformed India's idea of being an importer of healthcare facilities to becoming an expert and exporter of medical facilities, thus completely reversing the cycle of trade and global logistics in healthcare economic practices. This paper works on such an exploratory case study concerning India's success story in employing triple helix model of innovation in national policy practices and world economy.

A novel prediction model for cuttings bed height in horizontal and deviated wells

A better understanding of cuttings accumulation in the wellbore and ensuring favorable hole-cleaning conditions are crucial for successful oil and gas drilling operations. Considering the limited ability of existing critical velocity models to predict the cuttings bed height, and these models only consider the rolling transport mode of drill cuttings, improvement and development of new models are needed. This paper presents a new model for predicting the cuttings bed height over three possible transport modes of the target bed particle: sliding, rolling, and lifting. A mechanical equilibrium relationship of the particle in the critical condition is established and to calculate the bed-friction velocity of different transport modes. The transport mode can be judged by comparison among the minimum calculated values. The mean annular velocity and cuttings bed height can be calculated according to the borehole geometry information and eccentricity. The model can be applied to drilling fluids with different flow patterns (laminar, turbulent) and different rheological models (Newtonian fluid such as water, non-Newtonian fluid conforming to Power-Law or Herschel-Bulkley models). The effects of inclination angle, cuttings size, circulation velocity, rheological parameters, eccentricity, and hole size on mean annular velocity and cuttings bed height were analyzed. Cuttings transportation experiments were carried out on a large-scale flow loop to validate the theoretical analysis results by comparison against the experimental results. This work has certain guiding significance for predicting the hole cleaning degree in the annulus, as well as the subsequent optimization of hydraulic parameters and the implementation of hole-cleaning measures.

Substrate concavity influenced evaporation mechanisms of sessile droplets

In this article, we probe the morphing of the evaporation kinetics of sessile droplets on curved hydrophilic and superhydrophobic (SH) surfaces. Concave grooves of different radii have been employed, and optical diagnostics of the droplet profile has been carried out to monitor evolution of the evaporation progress. Our observations reveal curtailed evaporation rates on curved hydrophilic surfaces due to the droplet confinement phenomenon, whereas the rates improve for curved SH surfaces. We study the modulation of triple line transients and contact angle dynamics under the influence of substrate curvature. We show that the effective evaporation rate is determined by the interplay of substrate curvature and a proposed confinement ratio. Furthermore, the internal flow field within the evaporating droplet is studied using particle image velocimetry. Our findings show that minor changes in internal velocity occur due to hydrophilic substrate curvature, whereas for a curved SH surface, the circulation velocity is augmented. A mathematical analysis based on diffusion driven evaporation is proposed to predict the transient variation of evaporation for curved hydrophilic substrates. We explain the enhanced evaporation rate on curved SH on the basis of enhanced circulation velocity and increase in liquid–vapor interfacial shear. The model predictions confirm well to the experimental observations.

Deep-learning based monitoring of FOG layer dynamics in wastewater pumping stations

Accumulation of fat, oil and grease (FOG) in the sumps of wastewater pumping stations is a common failure cause for these facilities. Floating solids are often not transported by the pump suction inlets and the individual solids can accumulate to stiff and thick FOG layers. The lack of data about the dynamics in FOG layer formation still hampers the design of effective measures towards its mitigation. In this article, we present a low-cost camera-based automated system for the observation of FOG layer dynamics in wastewater pumping stations at high-frequency (minutes) over extended time windows (months). Optical imagery is processed through a deep-learning computer vision routine that allows describing FOG layer dynamics (e.g. accumulation rate and changes in shape) and various hydraulic processes in the pump sump (e.g. the water level, surface flow velocity fields, vorticity, or circulation). Furthermore, the system can perform in-camera image processing, thus allowing the transfer of compressed-processed datasets when deployed in remote locations (Edge AI computing), which could be of great utility for the hydro-ecological monitoring community. In this study, the technology applied is illustrated with a dataset (six months, two-minute frequency) collected at a wastewater pumping station at the municipality of Rotterdam, The Netherlands. This monitoring system represents a source of information for the management of (waste)water pumping stations (e.g. detection of free-surface vortices and scheduling of sump cleaning operations) and facilitates the collection of standardized high-frequency FOG layer dynamics data for a detailed description of FOG build-up and transport processes.

Simulation of the Circulating Motion of the Working Medium and Metal Removal during Multi-Energy Processing under the Action of Vibration and Centrifugal Forces

The rotational motion of the medium granules under the influence of an impeller installed in the bottom of a cylindrical reservoir is considered. The dependencies of the circulation velocity of the abrasive granules, as well as the dependence of the pressure in the circulation flow of the granules on the radius of the vibrating machine cylindrical reservoir for different speeds of the impeller rotation are obtained. Furthermore, the velocities of the abrasive granules at various distances from the center of the cylindrical reservoir of the vibrating machine have been determined. The amplitudes of the tangential and radial components of the velocity of movement of pseudo-gas from abrasive granules are obtained. The total pressure on the surface of the processed part and the average velocity of the abrasive granules colliding with it are determined. The graphical dependencies of the integral metal removal on the amplitude and frequency of oscillations of the walls of the vibrating machine reservoir are given for various values of the angular velocities of the impeller rotation.

CO2 removal using 1DMA2P solvent via membrane technology: Rate based modeling and sensitivity analysis

A numerically solved reaction rate/kinetic model for CO2 removal from a CO2/N2 gas mixture into novel reactive 1-dimethylamino-2-propanol (1DMA2P) solution in a gas–liquid membrane contactor was constructed. The model is assembled by considering the main transport phenomena and all possible reactions. The validated model was applied to investigate the transport phenomena in the different sides of membrane. The impact of main operation parameters on the performance of HFMC were evaluated. The influence of co- and counter-current operational modes on the absorption process was analyzed. The sensitivity analysis under moderate conditions indicated that the mass transfer resistance of gas phase is dominant with respect to liquid phase. Enhancing the liquid temperature, solvent circulation velocity, 1DMA2P concentration and also decreasing gas stream velocity increase the CO2 absorption. The CO2 removal using conventional and alternative amines were analyzed and compared. It is observed that due to high capacity of 1DMA2P for CO2 capture and its low regeneration heat, it could be considered as one of the efficient solvent for CO2 removal.

KEMAJUAN TEKNOLOGI DAN KECEPATAN PERPUTARAN UANG: STUDI KASUS INDONESIA

Technological developments and financial innovations, especially in the payment system, have encouraged banks around the world to carry out a number of innovations that have resulted in a new paperless based financial system. The finding that the payment system innovation affects the circulation of money and the stability of the monetary condition of a country, makes this risk possible in Indonesia. By using the error correction model, this study can provide information on the short run dynamic relationship and the impact of payment system innovation represented by non cash payment instruments such as credit cards, debit cards, e-money and payment transaction settlement processes (national clearing system and real time gross settlement) on the velocity of money in Indonesia in the period 2016M1 to 2020M6. The results of the research findings state that the impact generated by the rapid velocity of payment system innovation on the velocity of money circulation is not temporary, this is evidenced by the effect of payment system innovation on the velocity of money circulation which continues over a long period of time.

Numerical and Experimental Analysis of Flow and Pulsation in Hump Section of Siphon Outlet Conduit of Axial Flow Pump Device

In order to study the variation law of the flow field and pressure fluctuation in the hump section of the siphon outlet conduit, the flow field characteristics and frequency spectrum characteristics of the flow field were analyzed by combining a physical model test and numerical simulation under the conditions of the interaction between the axial flow pump and siphon outlet conduit, and the influence of the residual circulation at the outlet of the guide vane on the siphon outlet flow was investigated. Based on the influence of the flow field and hydraulic loss in the conduit, the equivalent surface method based on the Q criterion was used to analyze the vortex structure in the siphon outlet conduit and to analyze the internal vortex state. The results showed that with the increase of the flow rate, the intensity of the vortices in the cross-section of the hump section of the siphon outlet conduit decreased gradually, the average velocity circulation decreased gradually and the axial velocity distribution uniformity increased and tended to be stable; water flow stratification existed under three characteristic conditions with no circulation, and the hydraulic loss was greater with the circulation flow while it had a circulation under the small flow condition. Under the low flow rate conditions, the hydraulic loss was 6.6 times higher under the condition of circulation than without. Under a high flow condition, it was 1.3 times. Under the condition of a small flow rate, the vortex structure was distributed centrally at the inlet of the flow conduit, and under the other two characteristic conditions, the vortex structure mostly appeared as a strip; the pressure fluctuation in the hump section had obvious periodicity, and with the increase of the flow rate, the maximum pressure fluctuation amplitude in the hump section decreased gradually; with the decrease of the rotational speed, the pressure amplitude at the same measuring point in the hump section decreased gradually and at the optimum condition. Under the following conditions, the mean value of the pressure amplitude at the top of the hump section was reduced by 69.63%, and the mean value of the pressure amplitude at the bottom of the hump section was reduced by 63.5%. Under all the calculation conditions, the main frequency of pulsation at each measuring point of the hump section was twice the frequency of the rotation.

Rotational velocity of a relativistic heat conducting fluid configuration in non-circular axisymmetric stationary spacetime

The present work is focused to study the rotational velocity of a heat conducting fluid configuration based on Carter’s model and related consequences under the assumption that the background space time is non-circular stationary and axi symmetric. The level surfaces of constant angular velocity about rotation axis do not coincide with level surfaces of constant effective angular momentum per baryon corresponding to the matter part of fluid because of the variation of Killing twist scalars coupled with thermodynamic quantities in meridional planes. The rotation of matter part of fluid bears an intrinsic relationship with heat flow, injection energy per baryon, chemical potential of matter part of fluid, and rotational potential created by dynamic space time as an outcome of interaction between the motion of the entropy fluid and of the matter part of fluid. The meridional circulation velocity plays a key role in the creation of the entropy production besides the contributions made by other thermodynamic quantities. The entropy fluid is not co rotating with the matter part of fluid in the presence of dissipation caused by the heat flow. It is found that a linear combination of the injection energy gradient and the gradient of rotational velocity about rotation axis is constant along the matter part of fluid flow lines.

Effect of nature-inspired needle-shaped vortex generators on the aerodynamic features of a double-delta wing

The effects of using nature-inspired needle-shaped vortex generators (VGs) on the aerodynamic features of a 65°/35° double-delta wing were investigated experimentally in a wind tunnel. Particle Image Velocimetry (PIV) visualization was conducted on 7 chord-wise sections as well as 7 span-wise sections at an Angle of Attack (AOA) of 30° and on a plane adjacent to the wing surface at AOAs of 30° and 35° The experiments were carried out at Re = 2 × 105. The double-delta wing was equipped with a series of VGs at the leading edge of the apex and kink area. The effect of VGs on the time-averaged vortical flow features was investigated and then compared to those of the plain wing model. The assessment of the vortices’ diameter, vorticity and velocity distribution, streamline topology, circulation (Γ), and parameter Γ/Av showed that the use of the needle shaped VGs has an enhancing effect on the improvement in flow structure of the double-delta wing. The causes of the flow structure improvement were the increased flow momentum over and behind the wing, energized near-surface flow, a more concentrated vortex system, and delayed vortex breakdown.

Kemajuan Teknologi dan Kecepatan Perputaran Uang: Studi Kasus Indonesia

Technological developments and financial innovations, especially in the payment system, have encouraged banks around the world to carry out a number of innovations that have resulted in a new paperless based financial system. The finding that the payment system innovation affects the circulation of money and the stability of the monetary condition of a country, makes this risk possible in Indonesia. By using the error correction model, this study can provide information on the short run dynamic relationship and the impact of payment system innovation represented by non cash payment instruments such as credit cards, debit cards, e-money and payment transaction settlement processes (national clearing system and real time gross settlement) on the velocity of money in Indonesia in the period 2016M1 to 2020M6. The results of the research findings state that the impact generated by the rapid velocity of payment system innovation on the velocity of money circulation is not temporary, this is evidenced by the effect of payment system innovation on the velocity of money circulation which continues over a long period of time.

An Experimental-Numerical Investigation of the Wake Structure of a Hovering Rotor by PIV Combined with a Γ2 Vortex Detection Criterion

The rotor wake aerodynamic characterization is a fundamental aspect for the development and optimization of future rotary-wing aircraft. The paper is aimed at experimentally and numerically characterizing the blade tip vortices of a small-scale four-bladed isolated rotor in hover conditions. The investigation of the vortex decay process during the downstream convection of the wake is addressed. Two-component PIV measurements were carried out below the rotor disk down to a distance of one rotor radius. The numerical simulations were aimed at assessing the modelling capabilities and the accuracy of a free-wake Boundary Element Methodology (BEM). The experimental and numerical results were investigated by the Γ2 criterion to detect the vortex location. The rotor wake mean velocity field and the instantaneous vortex characteristics were investigated. The experimental/numerical comparisons show a reasonable agreement in the estimation of the mean velocity inside the rotor wake, whereas the BEM predictions underestimate the diffusion effects. The numerical simulations provide a clear picture of the filament vortex trajectory interested in complex interactions starting at about a distance of z/R = −0.5. The time evolution of the tip vortices was investigated in terms of net circulation and swirl velocity. The PIV tip vortex characteristics show a linear mild decay up to the region interested by vortex pairing and coalescence, where a sudden decrease, characterised by a large data scattering, occurs. The numerical modelling predicts a hyperbolic decay of the swirl velocity down to z/R = −0.4 followed by an almost constant decay. Instead, the calculated net circulation shows a gradual decrease throughout the whole wake development. The comparisons show discrepancies in the region immediately downstream the rotor disk but significant similarities beyond z/R = −0.5.

The effect of aspect ratio on PCM melting behaviour in rectangular enclosure

ABSTRACT The effect of Aspect ration on melting process of PCM (polyethylene glycol 1500 (PEG 1500)) in a rectangular encloser was investigated using CFD modelling. The CFD model was validated by experimental measurement performed for one case of aspect ratio of 2.31 with height = 155 mm, width = 67 and depth = 200 mm. The study was conducted in two phases: i) constant height enclosure, ii) constant volume enclosure. The main conclusions from this study are: i) the conduction heat transfer is the only mode of heat transfer in the first 250 secs from the start of heating of PCM. Then, the evolution of natural circulation starts at the hot wall and developed to a complete steady cycle after 2000 secs. ii) the results indicate a clear effect of the aspect ratio (AR) on melting percentage with peak at AR = 2,31 for both cases of constant heght and constant volume. iii) the results also show that there is a limiting width of the encloser where the circulation velocity reduced to low values (<0.3 mm/s) regardless of the enclosure heht.

Analysis of productivity in raceway photobioreactor using computational fluid dynamics particle tracking coupled to a dynamic photosynthesis model

Raceway photobioreactors (RWPs) are the most common and affordable device for the mass culture of microalgae but due to geometry and the requirement of low input power, its photosynthetic performance is low. The fluid dynamics of RWPs have been studied for information such as energy dissipation and shear rate, CFD has never been used to analyze photosynthesis efficiency by coupling dynamic photosynthesis models with microalgae trajectories. In this work, we investigate by CFD simulation the effect of circulation velocities between 0.2 and 0.8 m s-1in a 0.15 m−1 deep RWPs under standard outdoor conditions to shows that in all circumstances the RWP from the point o view of photosynthesis operates as a perfectly segregated device (no mixing) and that the average growth rate is the result of the integration of the local growth rates at different depths (integration factor Γ = 0).

Velocity data-based determination of airfoil characteristics with circulation and fluid momentum change methods, including a control surface size independence test

An experimental method for determination of aerodynamic loads is presented. It is based on velocity vector field results obtained with Particle Image Velocimetry (PIV). As PIV is an optical measurement technique, the developed method for load determination can be defined as noninvasive. It is shown that the only information needed to estimate the lift and drag forces exerted on a body placed in the flow is a velocity distribution measured around the investigated object. Therefore, PIV results provide sufficient input experimental data to be used. Fundamental fluid mechanics theories were employed to develop algorithms for load estimation. Determination of the lift force is based on velocity circulation calculations. It is obtained by integrating the velocity field along a closed-loop encircling the body. An essential achievement made is the development of a procedure for finding an optimal size of the integration curve used for lift calculations. In the case of the drag force estimation, an analysis of fluid momentum changes has been used. The momentum deficit, within a given control volume containing the analysed aerofoil, is determined and related to the reaction drag force exerted on the body. Additionally, pressure field reconstruction based on velocity data, which enabled an application of small control surfaces and kept the drag estimation error at a satisfactorily low level, was introduced. The developed method was tested and verified with the reference computational fluid dynamics simulation results and applied further to the wind tunnel experimental data. A flow around the standard NACA0012 aerofoil at two flow regimes was investigated (Re=0.7times 10^5 and Re=1.4times 10^5). Lift and drag coefficient characteristics as a function of the angle of attack were obtained. An exceptional agreement between the experimental and reference numerical lift characteristics was attained (relative differences no larger than 5%). In the case of drag estimation, an acceptable level of similarity was observed (max. discrepancies below 20%).Graphic abstract

Far field geometric structures of 2D flows with localised vorticity

We show that 2D Navier–Stokes and Euler flows with localised vorticity always feature regular structures in the far field. The level lines of each component of the velocity, at large distances, tend to have the symmetries of a regular polygon: a digon if the total circulation is non-zero; a square for flows with zero total circulation and non-integrable velocity; an hexagon for flows with integrable velocity and, exceptionally, a polygon with more than six sides.

ANALYSIS OF THE DEMAND FOR MONEY AND THE VELOCITY OF MONEY IN THE DIGITAL ECONOMY ERA: A CASE STUDY IN INDONESIA

In the digital economy era, efficiency and effectiveness are required in carrying out all life activities, including transaction activities. The urge to payment innovates systems as an effort to meet the needs of the community has led to several new non-cash-based payment instruments, such as paperless-based payment transactions. The existence of non-cash transactions shifts the role of cash in society. This study aims to examine the effect of paperless-based non-cash payments represented by credit cards, debit cards, and electronic money on the demand and velocity of money in Indonesia. Using monthly data sourced from Bank Indonesia and the Central Statistics Agency for the period 2010M1-2019M11. The right analysis used to see the effect of payment system innovation on-demand and velocity of money circulation is the Error Correction Model. The findings in the literature state that there is a significant effect of paperless-based payments as a form of payment system innovation on the demand and velocity of money circulation in Indonesia. The strong influence between the demand for money and the velocity of money with paperless-based non-cash transactions in Indonesia in the long term indicates that policymakers need to be careful in making decisions. The long-term relationship explains that the central bank can influence people's transaction behavior. Given that currency in circulation forms a significant part of a central bank's balance sheet, the shrinking demand for currency will have important implications on the central bank's seigniorage income, its independence, and its ability to conduct monetary policy. Thus, it is important to check and understand the trend of money demand and the velocity of money so that it can provide long-term profits.

Prediction of PbLi fluid flow and temperature field in a thermal convection loop for qualification of fusion materials

Two modeling tools, a thermohydraulics code and a computational model in COMSOL Multiphysics, have been developed, tested and then applied to the analysis of fluid flow and heat transfer in a thermal convection loop (TCL). Such a device has recently been used to experimentally evaluate corrosion compatibility of APMT (Fe–21Cr–5Al–3Mo) steel with high-temperature molten eutectic lead-lithium (PbLi) alloy at Oak Ridge National Lab, TN, USA. The 1-D thermohydraulics code allows for rapid calculations of the loop parameters as a function of the applied heat flux. The supplemental COMSOL finite-element computations provide detailed 3-D velocity and temperature field data but are much more time consuming. Both modelling tools demonstrate an excellent agreement in the computed circulation velocity as well as maximum and minimum temperatures. The performed TCL analysis focuses on flow development in the “hot” and “cold” legs, formation of Dean vortices in corner regions, blocking effect of the immersed samples, and radiative and convective cooling effects under the experiment-relevant conditions for Prandtl number Pr=0.015, Grashof numbers Gr∼107, and Reynolds numbersRe∼104.

Crisis and the Role of Money in the Real and Financial Economies—An Innovative Approach to Monetary Stimulus

‘Financial crisis’ is sometimes regarded as synonymous with ‘economic crisis’, but this is an oversimplification and risks missing the feedback loops between the financial and real economies. In this paper, the role of money is revisited in the context of distinguishing the real economy from the financial economy. A theoretical framework is developed to explain how endogenous (bank credit) and central bank exogenous (quantitative easing, QE) money creation feed into the real and financial economies. It looks at how the velocity of monetary circulation varies between the two economies and across asset types within the financial economy. Monetary transmission mechanisms are set into a framework that helps explain how QE stimulus risks combining asset price bubbles with poor growth in the real economy. The real economy transmission mechanism of ‘helicopter money’ is given context, enabling an assessment of the efficacy of both the QE and helicopter money policy routes. Finally, we present a new type of monetary transmission, ‘Smart Helicopter Money’, to deliver monetary stimulus to innovators, SMEs and high-growth firms via both complementary currencies and a modified form of QE in order to achieve proportionally greater impact on the real economy.

Revealing the influence of high magnetic field on the solute distribution during directional solidification of Al-Cu alloy

The effect of the high magnetic field (MF) on the distribution of solute concentration during directional solidification of Al-Cu alloy under low growth speed was experimentally investigated. The amount of non-equilibrium eutectic is quantified via X-ray computed tomography (XCT) and demonstrated to reduce with the application of MF. Further, experimental results reveal that the MF alleviates the microsegregation and increases the average Cu concentration in solid solution, leading to the increases of the effective partition coefficient ke. It was also found that Cu concentration in solid solution increases continuously with the increasing intensity of MF, following the strengthening of micro-hardness. The change of ke under the MF is demonstrated to attribute to the thermoelectric magnetic convection (TEMC) in the mushy zone and the thermoelectric magnetic force (TEMF) acting on the solid. The TEMC is supposed to cause secondary convection owing to the inequality in flow velocities of circulation in different positions of dendrite stem. And the vacancies created by the proliferation and movement of dislocations induced by TEMF in the matrix is supposed to be able to capture solute atoms and thus enhance the solute concentration in the solid solution.