Tank Rotation Research Articles

Design of a New Supersonic Shock Wave Generator and Application in Power Generation

Wind energy is a kind of renewable energy with great potential for development. This study mainly investigated the application of shock waves generated by high-pressure gases (wind energy) for generating energy. In this study, we designed a new supersonic shock wave generator that can be reused without disassembling and assembling bolts and developed a shock wave monitoring system. It could measure the velocity of the generated shock waves at about Mach 3–5, and the output pressure exceeded 900 kg/cm2 (more than 100 times the input pressure). Then, we developed a power generation system driven by supersonic shock waves based on the characteristics of the new shock wave generator, which could generate high-pressure and high-speed blast waves and could be reused. The shock wave generator can repeatedly generate high-pressure waves to drive the Tesla turbine and then rotate the magnetic energy generator for power generation. This paper used tank pressure, output pressure, gas flow, rotation speed, voltage, and current detected by the system to conduct power generation performance analysis. When the minimum rotation speed was set to 1500 rpm and three bulbs were turned on as loads, the system could generate an average voltage of 36.64 V and an average current of 211.01 mA as output (power about 7731.41 mW).

Influence of cultivar, environmental conditions, and fungicides on development of Phytophthora root rot and wilt on red raspberry

Phytophthora root rot and wilt (PRRW), caused by Phytophthora rubi and potentially other species of Phytophthora, is a destructive disease of raspberry in Canada and worldwide. In this study, trials were conducted over multiple years (2019–2022) in two fields, with pathogen (P. rubi) inoculated (PI) and naturally infested (NI) fields, to evaluate foliar and soil applied fungicides with different modes of action and application timings to manage PRRW. In addition, PRRW progress was also monitored in one PI field and four NI fields. In PI field plots, PPRW foliage and wilting symptoms appeared 6–8 weeks later and disease index was significantly (p < 0.0042) lower in the cultivar ‘Cascade Bounty’ than the cultivars ‘Meeker’ and ‘Tulameen’, indicating that ‘Cascade Bounty’ showed field tolerance to the disease. The efficacy of foliar fungicides (fosetyl-Al and phosphites) and soil-applied fungicides (oxathiapiprolin, metalaxyl-m, and cyazofamid) were assessed on susceptible cultivars at both sites. In PI plots, the fungicide treatments significantly enhanced (p = 0.01 to < 0.0001) numbers of primocanes and floricanes, as well as weight, percent witling index, and fruit yield of floricanes. Soil application of a tank mix or rotation of oxathiapiprolin and metalaxyl-m, and alternating these products with cyazofamid, was more effective compared to other fungicides in reducing PRRW and improving plant vigor. Our study identified effective fungicide treatment options for PRRW, allowing growers to alternate new chemistries with currently registered fungicides to reduce the risk of fungicide resistance development.

Hydrodynamic Analysis of Partially Filled Liquid Tanks Subject to 3D Vehicular Manoeuvring

This paper is concerned with liquid sloshing in a partially filled container due to 3‐dimensional vehicle motion. The liquid sloshing is described by a set of linear modal equations derived from the potential flow theory, which can be applied to liquid sloshing induced by arbitrary combination of lateral, longitudinal, and rotational excitations. The sloshing force and moment are expressed with a set of hydrodynamic coefficients that are determined by the linear velocity potential. These coefficients can be precalculated and incorporated into the motion equations of the vehicle system so that a fully coupled vehicle‐sloshing model is available. In addition, we propose an approach to calculate the hydrodynamic coefficients using the outputs of commercial frequency‐domain boundary element software in order to maximize the efficiency of modelling and computation. The accuracy of the proposed model is examined by comparison with available CFD and model test data in the literature. The case of a road tanker encountering a road bump during acceleration/braking is investigated. Results show that the tank rotational motion will affect the amplitude and the sloshing force, and neglecting tank rotation may lead to underestimation of the sloshing force magnitude.

Direct numerical simulation of a bubble motion in a spherical tank under external forces and microgravity conditions

We present, in this paper, numerical simulations of bubble sloshing in a spherical tank, resulting from a tank rotation around a fixed axis in microgravity conditions. This configuration is of great interest in space applications where sloshing can have harmful effects on the stability of satellites. Depending on the dimensionless numbers characterising this phenomenon, our study is focused on the motion and the deformation of a bubble, initially at rest, which is set in motion when the manoeuvre is starting until it reaches a constant rotation speed around the axis. It is shown in this article that, during the first stage of the manoeuvre, the motion of the bubble is essentially driven by the inertial force that depends on the angular acceleration. Next, when the angular velocity is increasing, the centrifugal force being dominant, the trajectory of the bubble is pushed towards the direction between the centre of the tank and the axis of rotation. Finally, when the angular velocity becomes constant, the bubble, reaching a quasi-steady position, is deformed and pressed against the solid boundary of the tank. A quantified description of these phenomena is proposed through a parametric study varying the essential dimensionless numbers, i.e. the Bond number based on the angular velocity, and another Bond number based on the angular acceleration. As the temporal evolution of the forces acting on the satellite wall is of utmost importance for designing satellites and manoeuvres, we also present an analysis characterising the latter. We also detail the first comparisons between the numerical simulations and the Fluidics experiment performed in the International Space Station (ISS) in microgravity conditions. Thanks to these comparisons, we can validate the simulations in configurations of interest.

The role of periodically varying discharge on river plume structure and transport

We present results from laboratory experiments that simulate the effects of periodically varying discharge on buoyant coastal plumes. Freshwater is discharged into a two meter diameter tank filled with saltwater on a rotating table. The mean inflow rate, tank rotation period and density of the ambient salt water are varied to simulate a range of inflow Froude and Rossby numbers. The amplitude and the period of the inflow modulation are varied across a range that simulates variability due to tides and storms. Using the optical thickness method, we measure the width and depth of the plume, plume volume and freshwater retention rate in the plume. With constant discharge, freshwater is retained in a growing anticyclonic bulge circulation near the river mouth, as observed in previous studies. When the discharge is varied, the bulge geometry oscillates between a circular plume structure that extends mainly in the offshore direction, and a compressed plume structure that extends mainly in the alongshore direction. The oscillations result in periodic variations in the width and depth of the bulge and the incidence angle formed where the bulge flow re-attaches with the coastal wall. The oscillations are more pronounced for longer modulation periods, but are relatively insensitive to the modulation amplitude. A phase difference between the time varying transport within the bulge and bulge geometry determines the fraction of the bulge flow discharged into the coastal current. As a result, the modulation period determines the variations in amount of freshwater that returns to the bulge. Freshwater retention in the bulge is increased in longer modulation periods and more pronounced for larger modulation amplitudes.

Study of aircore phenomenon and influence of water height during liquid draining

Draining of liquids through cylindrical tanks is a very common phenomenon and has many applications. Understanding the aircore formation and its growth during draining has attracted appreciable interest in the literature. In this study, water draining through cylindrical tanks was studied using experimental and numerical techniques. Eight different initial heights of water in the tank between 310 and 450 mm with a 20-mm increment were tested in each experiment. The numerical study shows good agreement with the experimental data and promotes understanding of the generation and disappearance of an aircore during draining. For the different initial water heights, the experiments were performed with and without initial rotation of the tank. It is found that in the experiments without initial tank rotation, the drain time of water increases with increasing initial height. On the other hand, the drain time remains almost the same for all initial heights tested with initial tank rotation. The small variation in the drain time even when the initial water level is reduced is explained by the aircore duration during draining. Also, the mechanism of generation and disappearance of aircore is proposed with the help of numerical results.

Particle dispersion in a partially filled rotating cylindrical tank

Particles-liquid flow involving a free surface in partially filled rotating cylindrical tank is common in chemical engineering, which attracts numerical studies on it in an effort to provide useful information for the design and optimization of operational conditions in the real application. However, the dynamics of particles dispersion in partially filled rotating cylindrical tank under small particles-liquid density ratio has not been fully understood by performing a reasonable 3D numerical simulation. A three-dimensional unsteady model of a solid–liquid dispersed flow involving a free surface has been developed and numerically analyzed to investigate the particle dispersion in a partially filled rotating cylindrical tank. In the model, the discrete element method (DEM) and the volume of fluid (VOF) method have been applied. The flow field and the particle dispersion process in a rotational cylindrical tank have been presented. The effects of the tank rotation speed and the liquid height on the dispersion behaviors of particles are examined and analyzed. The results indicate that vortexes have formed in the liquid phase that entrain the particles and induce their gradual dispersion throughout the entire region of the liquid phase. The average mass concentration of particles is high in the rotating-out side of the liquid phase and in the liquid–wall contact region, while it is low in the rotating-in side of the liquid phase and in the vortex generation region. In addition, as the rotation speed increases, the entrainment capability of the liquid phase has been enhanced, which improves the dispersion performance of the particles. The selection of an appropriate liquid height is beneficial for the enhancement of particle dispersion in a partially filled rotating cylindrical tank.

An experimental investigation of forced steady rotating turbulence

This paper presents some of the principal findings of an experimental investigation of forced statistically steady turbulence in a rapidly rotating background. The experiment is conducted in a large cylindrical mixing tank and bulk rotation is produced by two large co-rotating impellers installed near the top and the bottom of the tank. The mean flow motion generated in such a configuration is axisymmetric and close to but not exactly solid-body rotation. The focus of this work is on the region in the vicinity of the rotation axis where the flow is Rayleigh stable. The unique features of this facility allow forcing and thus permit turbulence to be maintained at a certain level without a mean decay. The facility also allows an easy experimental access of statistical quantities. The bulk rotation rates and the amount of turbulence are adjusted to a Rossby number (Ro) of O(1). Under this condition, some physical phenomena commonly seen in solid-body rotating turbulent flows at low Ro are also observed, despite the differences in other parameters. A flow visualisation at one of the testing conditions using pearlescence clearly shows the presence of cyclonic columnar structures. Two-dimensional particle image velocimetry (2DPIV) measurements are carried out in a plane normal to the axis of the rotation and near the middle height of the tank. Symmetry breaking between cyclonic and anti-cyclonic vorticity in the flow is revealed by the skewness of the fluctuating vorticity. It is found that skewness is not a monotonic function of Ro; in this particular experimental arrangement, symmetry is broken to a maximum extent at Ro ∼1.5 based on velocity length scale. Turbulence quantities are also computed along with the turbulent energy dissipation, which is estimated using velocity structure functions and lends support to previous findings that purport that dissipation is suppressed in such flows.

Characterization of Phytophthora spp. Isolated from Ornamental Plants in Florida.

This report investigates population structure and genetic variability of Phytophthora spp. isolated from botanically diverse plants in Florida. Internal transcribed spacer-based molecular phylogenetic analyses indicate that Phytophthora isolates recovered from ornamental plants in Florida represent a genetically diverse population and that a majority of the isolates belong to Phytophthora nicotianae (73.2%), P. palmivora (18.7%), P. tropicalis (4.9%), P. katsurae (2.4%), and P. cinnamomi (0.8%). Mating type analyses revealed that most isolates were heterothallic, consisting of both mating type A1 (25.2%) and mating type A2 (39.0%), and suggesting that they could outcross. Fungicide sensitivity assays determined that several isolates were moderate to completely insensitive to mefenoxam. In addition, several isolates were also moderately insensitive to additional fungicides with different modes of action. However, correlation analyses did not reveal occurrence of fungicide cross-resistance. These studies suggest that a genetically diverse Phytophthora population infects ornamental crops and the occurrence of mefenoxam-insensitive Phytophthora populations raises concerns about disease management in ornamentals. Mitigating fungicide resistance will require prudent management strategies, including tank mixes and rotation of chemicals with different modes of actions.

Friction law and turbulent properties in a laboratory Ekman boundary layer

We use spin-up/spin-down laboratory experiments to study the neutrally stratified Ekman boundary layer. The experiments are performed in the 13 m diameter, 1 m deep Coriolis rotating tank of the LEGI in Grenoble, France. A global flow rotation is produced by an initial change in the tank rotation speed. It then slowly decays under the effect of Ekman friction, evolving from the turbulent state to the laminar state. It is checked that the Ekman layer itself remains in a quasi-steady state during this decay. The velocity is measured by Particle Imaging Velocimetry (PIV) at two scales: the global rotation in a horizontal plane, and the vertical profile inside the boundary layer, where the three velocity components are obtained by stereoscopic PIV. The friction law is obtained by relating the decay rate of the bulk velocity to the velocity itself. This method is justified by the fact that this bulk velocity is independent of height beyond the top of the boundary layer (a few cm), as expected from the Taylor-Proudman theorem for rotating fluids. The local measurements inside the boundary layer provide profiles of the mean velocity and Reynolds stress components, in particular the cross-isobar angle between the interior and near surface velocities. In the laminar regime, good agreement is obtained with the classical Ekman's theory, which validates the method. In the turbulent regime, the results are found consistent with the classical Atmospheric Boundary Layer (ABL) model based on the von Karman logarithmic layer. Our experiments therefore indicate that this theory, in principle valid for very large Reynolds numbers, is already relevant close to the transitional regimes. A fit of the empirical coefficients A and B appearing in this theory yields A = 3.3 and B = 3.0. Extrapolating the results to the atmospheric case gives a friction velocity u* about 12% higher than the traditional fit for the ABL. We may safely deduce that for the oceanic bottom boundary layer, corresponding to lower Reynolds numbers than the atmosphere, our result provides a correct estimate within 10%. The previous laboratory results of Caldwell et al. [“A laboratory study of the turbulent Ekman layer,” Geophys. Fluid Dyn. 3, 125–160 (1972)10.1080/03091927208236078] provided frictions velocities about 20% higher than in our experiments, and slightly higher cross-isobar angles. We attribute this difference to the higher vortical Rossby number Rot in those experiments, and maybe also to roughness effects. We take into account the effect of this vortical Rossby number within the framework of the Ekman layer (Rot → 0) by replacing the tank rotation rate by the fluid rotation rate.

Laboratory study of forced rotating shallow water turbulence

During the last three decades several authors have studied the appearance of multiple zonal jets in planetary atmospheres and in the Earths oceans. The appearance of zonal jets has been recovered in numerical simulations (Yoden & Yamada, 1993), laboratory experiments (Afanasyev & Wells, 2005; Espa et al., 2008, 2010) and in field measurements of the atmosphere of giant planets (Galperin et al., 2001). Recent studies have revealed the presence of zonation also in the Earths oceans, in fact zonal jets have been found in the outputs of Oceanic General Circulation Models-GCMs (Nakano & Hasumi, 2005) and from the analysis of satellite altimetry observations (Maximenko et al., 2005). In previous works (Espa et al., 2008, 2010) we have investigated the impact of the variation of the rotation rate and of the fluid depth on jets organization in decaying and forced regimes. In this work we show results from experiments performed in a bigger domain in which the fluid is forced continuously. The experimental set-up consists of a rotating tank (1m in diameter) where the initial distribution of vorticity has been generated via the Lorentz force in an electromagnetic cell. The latitudinal variation of the Coriolis parameter has been simulated by the parabolic profile assumed by the free surface of the rotating fluid. Flow measurements have been performed using an image analysis technique. Experiments have been performed changing the tank rotation rate and the fluid thickness. We have investigated the flow in terms of zonal and radial flow pattern, flow variability and jet scales.

Decay laws, anisotropy and cyclone–anticyclone asymmetry in decaying rotating turbulence

The effect of a background rotation on the decay of grid-generated turbulence is investigated from experiments using the large-scale ‘Coriolis’ rotating platform. A first transition occurs at 0.4 tank rotation (instantaneous Rossby number Ro ≃ 0.25), characterized by a t−6/5 → t−3/5 transition of the energy-decay law. After this transition, anisotropy develops in the form of vertical layers, where the initial vertical velocity fluctuations remain trapped. The vertical vorticity field develops a cyclone–anticyclone asymmetry, reproducing the growth law of the vorticity skewness, Sω(t) ≃ (Ωt)0.7, reported by Morize, Moisy &amp; Rabaud (Phys. Fluids, vol. 17 (9), 2005, 095105). A second transition is observed at larger time, characterized by a return to vorticity symmetry. In this regime, the layers of nearly constant vertical velocity become thinner as they are advected and stretched by the large-scale horizontal flow, and eventually become unstable. The present results indicate that the shear instability of the vertical layers contributes significantly to the re-symmetrization of the vertical vorticity at large time, by re-injecting vorticity fluctuations of random sign at small scales. These results emphasize the importance of the nature of the initial conditions in the decay of rotating turbulence.

Laboratory polarimetric measurements of microwave emission from capillary waves

The results of polarimetric microwave measurements of thermal emission from a water surface with artificial periodic structure are presented. The goal of the experiment is to verify the results of a model describing polarized microwave emission from gravity‐capillary waves on a sea surface. Periodic undulations of water surface were produced in a tank by a set of parallel nylon threads raised slightly above the mean surface. Due to surface tension, the water surface assumes a periodic profile; the amplitude of the roughness was changed by moving the frame with the threads up and down. The measurements of the three Stokes parameters of the emission were carried out with the Ka‐band polarimeter. The experimental setup allowed measurements to be made over a wide range of view angles (from near‐nadir to 70°). The tank rotation allowed variation of the azimuthal angle between the periodic structure and the observation plane of more than 300°. The experimental data show the existence of the resonant peak in the Stokes parameters predicted by the model. The amplitude of the peak reached 10 K. Also, drastic contrasts were registered in the azimuth dependencies of the Stokes parameters. This result is evidence of the important role that short gravity‐capillary waves play in sea‐surface polarized microwave emission.

Rotating Convection Driven by Differential Bottom Heating*

Convection experiments were carried out in a rectangular tank as a model of oceanic meridional overturning circulation. The objective was finding a relation between the meridional heat flux and thermal forcing. To make the meridional heat flux estimate possible, the heat flux was fixed at one bottom end of the tank using an electrical heater. Temperature was fixed at the other end using a cooling plate. All other boundaries were insulated. In equilibrium, the heat input to the fluid H was the same as the meridional heat flux (heat flux from the source to the sink), so it was possible to find a scaling law relating H to the temperature difference across the tank DT and rotation rate f. The experimental result suggests that the meridional heat transport in the experiment was mostly due to geostrophic flows with a minor correction caused by bottom friction. When the typical values of the North Atlantic are introduced, the geostrophic scaling law predicts meridional heat flux comparable to that estimated in the North Atlantic when the vertical eddy diffusivity of heat is about 1 cm 2 s21.

Modeling and Motion Control of Fluid Behavior in Automatic Pouring System

This paper is concerned with modeling, simulation and control of an automatic pouring system of tilting-type considering the fluid behavior. A mathematical model is built using two dimensional continuity and Navier-Stokes equations with the term of tank rotation. Model validity is confirmed by laboratory experiments of water model. Using a numerical simulator developed in this paper, the effect of operated variables like the tank shape and the angular velocity of tank rotation is analysed on the fluid behavior during pouring. Sloshing and flow rate control are also discussed.

Free Vibration Analysis of Liquid Motion in a Rotating Circular Cylindrical Tank (Elliptic Mode).

Free vibration analysis is presented for liquid surface motion in a rigid circular cylindrical tank which is rotating around its symmetrical axis at constant angular velocity. It is considered that the equilibrium surface forms a paraboloid of revolution. Basic equations of liquid motion are derived by using the acceleration potential under the assumptions that the gravity. effect is dominant in comparison with the centrifugal force and that the liquid is inviscid and incompressible. It is confirmed that both elliptic and parabolic vibration modes of free surface oscillation appear due to tank rotation. The characteristic equations for the elliptic modes are derived by applying Galerkin's method. It is noted that the natural frequencies of the elliptic mode are separated by the Coriolis force. An experiment was conducted using a model tank. A good agreement was found between the theoretical and experimental results.

Topographic Effects on the Mean Tropospheric Flow Patterns around Antarctica

Abstract Topographically induced flows around Antarctica in a rotating tank experiment with both homogeneous and stratified fluid are analyzed and compared with the mean tropospheric circulation. A circular tank of fluid was brought to a state of near-rigid clockwise rotation, and a topographic model of the Antarctic continent was then rotated counterclockwise to simulate a mean westerly zonal wind. Stratification was chosen to give the same ratios of topographic and dynamical length scales as in the atmosphere, as was the Rossby number based on the ratio of rotation rates. After the onset of the relative rotation of the Antarctic model, cyclonic eddies evolved in the coastal areas with, in the homogeneous case, anticyclonic eddies over the Antarctic dome. After about ten tank rotation periods, a dominant wavenumber 3 structure with cyclonic eddies in the Ross and Weddell seas and Prydz Bay is observed as an approximately steady state. Flow over the topography is relatively stagnant, with weak anticycloni...

Seismically Induced Fluid Forces on Elevated Tanks

Seismically induced fluid forces on elevated liquid storage tanks and their supporting systems are evaluated. X-braced as well as pedestal towers are analyzed. The interaction between liquid sloshing modes, tank rotation, tank translation and tank wall flexibility is taken into consideration to assess the relative importance of such effects on the overall earthquake response of elevated tanks. Ideal liquids and elastic towers are assumed throughout the first phase of the study. A comparison between the calculated forces and those provided by applicable codes is made.

A note on the internal Kelvin waves generated by tidal flow over a two‐dimensional ridge in a rotating fluid

A number of experiments on the internal Kelvin waves generated by tidal flow over a two‐dimensional ridge have been performed in a long, narrow rotating tank. The plan form, phase speed, amplitude, and induced velocity of the internal Kelvin waves were observed for several tidal periods, tank rotation rates, and density differences.

The residence time of air bubbles &amp;lt;400 &amp;#x3bc;m diameter at the surface of distilled water and seawater

Air bubbles from 50 to 400 μm diameter were produced from a fine capillary tip inserted through the top of a rotating tank of water. Bubble persistence on the surface was measured from the tank geometry and rotation rate, the minimum detectable time being 10 -2 s. In distilled water, nearly all bubbles >200 μm diameter persisted <0.05 s, but smaller bubbles existed for several seconds or more. Opposite results were found in seawater. Bubbles less than about 80 μm diameter existed ≤10 -2 s. For larger bubbles, the residence time increased with size. reaching about 0.3 s for bubble diameters of 300 μm. These results, plus other experiments. suggest that bubble collisions in seawater will produce coalescence if one of the bubbles is less than about 80 μm diameter. DOI: 10.1111/j.1600-0889.1984.tb00249.x