Free-boundary plasma equilibria with toroidal plasma flows

Magnetohydrodynamic equilibrium schemes with toroidal plasma flows and the scrape-off layer are developed for the 'divertor-type' and 'limiter-type' free boundaries in the tokamak cylindrical coordinator. With a toroidal plasma flow, the flux functions are considerably different under the isentropic and isothermal assumptions. The effects of the toroidal flow on the magnetic axis shift are investigated. In a high beta plasma, the magnetic shift due to the toroidal flow are almost the same for both the isentropic and isothermal cases, and are about 0.04a0 (a0 is the minor radius) for M0=0.2 (the toroidal Alfvѐn Mach number on the magnetic axis). In addition, the X-point is slightly shifted upward by 0.0125 a0. But the magnetic axis and the X-point shift due to the toroidal flow may be neglected because M0 is usually less than 0.05 in a real tokamak. The effects of the toroidal flow on the plasma parameters are also investigated. The high toroidal flow shifts the plasma outward due to the centrifugal effect. Temperature profiles are noticeable different because the plasma temperature is a flux function in the isothermal case.

Numerical Simulation of Internal Flow Field in Turbo-Expander

As everyone pays more attention to energy consumption, it is very meaningful to use natural gas pressure energy for power generation and turbo-expander is an important part of power generation devices. In this paper, the turbo-expander model for pressure energy generation is meshed and numerically simulated based on fluent, and the pressure distribution and velocity distribution in the turbo-expander are obtained. The volute profile is Archimedes spiral, and the impeller is modeled by cfturbo. The main conclusions are as follows: when the number of grids is more than 2.2 million, the simulation results are less affected by the number of grids. The internal basin of the turbo-expander has obvious pressure gradient and velocity gradient. Due to the negative pressure at the elbow of the inlet pipe of the centrifugal effect, the existence of the blade leads to the change of the flow direction. Different watershed planes have different pressure and velocity distributions. The velocity and pressure of the watershed plane near the impeller outlet and the volute outlet are often smaller, but the flow vortex is more intense.

Inverse centrifugal effect induced by collective motion of vortices in rotating thermal convection

When a fluid system is subject to strong rotation, centrifugal fluid motion is expected, i.e., denser (lighter) fluid moves outward (inward) from (toward) the axis of rotation. Here we demonstrate, both experimentally and numerically, the existence of an unexpected outward motion of warm and lighter vortices in rotating thermal convection. This anomalous vortex motion occurs under rapid rotations when the centrifugal buoyancy is sufficiently strong to induce a symmetry-breaking in the vorticity field, i.e., the vorticity of the cold anticyclones overrides that of the warm cyclones. We show that through hydrodynamic interactions the densely distributed vortices can self-aggregate into coherent clusters and exhibit collective motion in this flow regime. Interestingly, the correlation of the vortex velocity fluctuations within a cluster is scale-free, with the correlation length being proportional ( ≈ 30%) to the cluster length. Such long-range correlation leads to the counterintuitive collective outward motion of warm vortices. Our study brings insights into the vortex dynamics that are widely present in nature.

Law of Physics 20th-Century Scientists Overlooked (Part 5): Centrifugal Effect Negation

Explored is another application of the phenomenally successful DSSU’s aether theory of gravity. It is explained how rotational motion with respect to the universal space medium (aether) determines the centrifugal effect. The article details the conditions involved in the attenuation of the Effect; and the extreme condition under which complete negation occurs. Included is a description of how a totally collapsed star —called a Terminal neutron star— is unable to manifest any centrifugal effects; and how, consequently, it can have no theoretical limit on its rate of rotation. Revealed is the fundamental law governing circular motion. This long-overlooked principle of physics leads to a startling and profound implication: Spiral galaxies are able to maintain their structural integrity without the need for so-called dark matter.

The Geomorphological Factors and Its Implications for The Tidal Energy Installations in Java, Indonesia

This study aims to place the tidal energy installation effectively in Indonesia based on geomorphological factors. The survey method was used to analyze the characteristics of beaches in Indonesia. Mathematical physics model was implemented to find the new formulas based on geomorphological factors. Tides are the result of gravitational attraction and the centrifugal effect, which is the drive In the earth-moon system, tidal generating forces are the resultant forces that cause tides, namely: the earth-moon system (FS) centrifugal force and the moon's gravitational force (FB). FS works in the center of the mass of the earth-moon system whose mass point is located on the 3/4 radius of the earth. The style of tidal generator caused by the moon can be calculated by combining Newton's universal gravitational law .The results of this study consist of F = m ac, where the style of the tidal generator caused by the moon can be calculated by combining newton's universal gravitational law in equation and newton's second law of motion in Equation. The another results is tan = , where the formula takes into account constants (K) based on slopes. The last result is the constants (K) for each land form starting on 0,00 untill 1,00. The north coast of Java is more suitable for tidal energy installations because the land form is dominated by alluvium plains of the quaternary age with a lower risk than the southern region of Java. The effectiveness of tidal energy installation depends on the characteristics of the land form. In alluvial plains, the quaternary age of the alluvial plains is more suitable than the hill form volcanic quaternary, tertiary volcanic, and tertiary holokarst.

A new bladed assembly simulator and an improved two-parameter plot method for blade tip-timing numerical simulations

The blade tip-timing measurement technique is presently the most promising technique for monitoring the blades of axial turbines and aircraft engines in operating conditions. Due to the high cost of experimental simulations of blade tip-timing–based condition monitoring methods, a numerical simulator for the vibrational behavior of bladed assemblies can be helpful for researchers interested in this field. So far, in most of the numerical simulators, the centrifugal effect of rotational speed on the natural frequencies is neglected. In this study, a new bladed assembly considering the centrifugal effect of the rotational speed for blade tip-timing numerical simulations is proposed. Moreover, an improvement in the engine order estimation algorithm in a two-parameter plot method is accomplished. In the assembly, blades are assumed to be cantilevered Euler–Bernoulli beams coupled together using linear springs. The finite element method is used to extract mass and stiffness matrices from differential equations of the system. By using the two-parameter plot method, the engine order of the excitation is detected. To examine the performance of the algorithm, Monte–Carlo simulation is implemented. The new simulator fulfills both cyclic symmetry and increase in the natural frequencies with increase in rotational speed. Engine order estimation with the new formulation in the two-parameter plot method is accurate. Hence, the new simulator and formulation for two-parameter plot method are reliable for numerical simulations.

Synthesis, Spectral and Thermal Characteristics of Silica/PVP Nanofluids

Nanofluid is well known as smart fluid which has high ability to recover oil. Therefore, it gains more significant effect in oil and gas industry. With the low concentration of nanofiller in nanofluid is used to enhance the numerous characteristics for oil recovery applications. Then, the main feature is the size of reinforcing agent and properties along matrix medium. Nano dimensional particles suspension in polymeric matrix have major advantages are stable sedimentation, optical, mechanical, electrical, and rheological properties that can be affected during the synthesis of nanofluids. Therefore nanoparticles/polymeric nanofluid have exceptional characteristics over the conventional fluid. Mixed nanoparticles/polymeric nanofluid in the presence of surfactant have effective interfacial tension and wettability which is evident for the development of nanofluids for oil recovery. In this context, the designed experimental study of silica/PVP nanofluids is synthesized via two step methods and characterized by SEM, TG/DTA, contact angle measurement, centrifugal effect and sedimentation test intended for Enhanced Oil Recovery (EOR) system.