Turbulent Movement Research Articles

The effect of fabric movement on washing performance in a front-loading washer III: Focus on the optimized movement algorithm

The objectives of this study were to investigate the correlation between fabric movement and washing efficiency in a front-loading washer and to make an algorithm for improving washing efficiency by optimizing fabric movements. A regression model between fabric movement and washing efficiency was made using 14 movement indexes. The angle change of the fabric gravity center, the speed difference between the drum and the fabric, and the shape factor were found to be determining factors for washing efficiency. Various kinds of wash spin speed were employed for making a complex movement algorithm, since it was found that turbulent or complex movement improves the washing efficiency. The optimal algorithm saved energy (25%) and time (27%), as well as achieving higher washing efficiency (4.8%).

Analysis of particle behaviors using a region-dependent method in a jetting fluidized bed

The analysis of the flow hydrodynamics in jetting fluidized beds is of considerable significance as it is widely applied in pharmaceutical, food, chemical, and petrochemical industries. In this study, an improved sub grid scale (SGS) model in the large eddy simulation (LES) method has been used based on a discrete hard sphere particle model in a jetting fluidized bed. The comparison of simulation results with experimental data shows that the improved SGS method, with a mutative Smagorinsky constant SGS approach, results in a better agreement than when using an invariant constant. Furthermore the particle behavior was analyzed by a region-dependent analysis method to obtain the spatial relationship of the particle behavior. The tendency of macro particle behavior is quite different from that at the micro level, which means that the fluctuation in the bed is not related to the overall particle movement. The particle macro characteristics can be affected by multiple factors such as the type of gas in the jet, the type of particles and the bubbles in the bed. The granular temperature distribution, which is related to the micro turbulent movement, presents strong anisotropic features, and specific rules of bubble and particle behavior are deduced. The region-dependent analysis method is also discussed in this work.

A Case Study of the Upwind Urbanization Influence on the Urban Heat Island Effects along the Suzhou–Wuxi Corridor

AbstractThe urban heat island (UHI) effect is one of the most significant phenomena caused by urbanization. This study investigated the UHI effect in the Suzhou–Wuxi area, China, on 19–20 August 2010. Using a combination of meteorological station observations and Moderate Resolution Imaging Spectroradiometer (MODIS) surface skin temperature observations, this study demonstrated that an upwind UHI had an exacerbating influence on the downwind UHI during the study period. Numerical simulations using the Weather Research and Forecasting model also proved the importance of an upwind UHI influence on the leeward UHI in this area. For the near-surface UHI, the windward UHI effect is stronger at night than during the daytime because the background atmospheric stratification is more stable and the local lake breeze is weaker at night. However, in the daytime, a greater stability formed over the downwind city because of the warmer air heated by the windward urban area in the upper part of the planetary boundary layer and the cooler air transported from Tai Lake and the rural area in the lower part of the boundary layer. In comparison with the heating effect of a single city, the upwind UHI led to a decrease in the vertical wind speed of approximately 30% (from 0.15 to 0.10 m s−1) in the upper boundary layer over the downwind city and also reduced the near-surface turbulent movement by 25% (from 0.73 to 0.55 m2 s−2). These results improve the understanding of the overall influence of urban clusters on local synoptic/climate processes.

New insights into turbulent pedestrian movement pattern in crowd-quakes

Video recordings right before the Love Parade disaster have been quantitatively analyzed to explore the bursts of unusual crowd movement patterns, crowd-quakes. The pedestrian movement pattern in this incident was special for the reason that it happened in a congested counter flow scenario, where stopped pedestrians were involved. No one was believed to have pushed others intentionally at the beginning, however, under this situation, the body contacts among the pedestrians still induced a force spread, which then led to velocity fluctuation. As indicated by the individual velocity-related features, the densely crowded pedestrian movement displayed turbulent flow features. Further analyzing the overall flow field, we also found that the pedestrian flow field shared typical patterns with turbulent fluid flow. As a result of the turbulent state, different clusters of pedestrians displayed different velocity features. Thus crowd pressure which took into account the velocity and density information was proved to be a good indicator of crowd disasters. Based on these essential features of pedestrian crowd-quakes, a minimal model, i.e., a pedestrian crowd-quake model, was established. Effects including pedestrian gait, stress conservation level and personal intention to escape were explored.

Hybrid RANS–LES wake studies of an airfoil in stall

Numerical simulations of the flow about a NACA 0012 airfoil in low speed stall conditions are presented. The focus is set on the propagation of turbulence in the wake of the airfoil. The calculations were performed at a Mach number of 0.3, a Reynolds number of 6 million and an angle of attack close to maximum lift. The unstructured finite-volume solver TAU, which is developed by the German Aerospace Centre, was used to simulate the unsteady flow in the vicinity of the airfoil and its wake up to two chord lengths downstream. Hybrid turbulence models are used to represent the attached part of the boundary layer with the Reynolds-averaged Navier–Stokes equations (RANS) and the detached regions with large eddy simulation (LES). This enables a direct resolution of the large-scale turbulent movement in the separated regions and the wake behind the airfoil. The simulations were conducted on different meshes with increasing resolution. The capability of two hybrid RANS–LES models of detached eddy simulation type is investigated in representing the turbulent characteristics of the far wake. The influence of the mesh properties and the modeling approach is discussed. Hence the pressure spectra in the wake are compared to experimental data. Due to good agreement of the improved DDES results with the measurement data, the wake of the airfoil is evaluated over a long time period. The development of pressure and velocity spectra along the wake is discussed.

The data cyclotron query processing scheme

A grand challenge of distributed query processing is to devise a self-organizing architecture which exploits all hardware resources optimally to manage the database hot set, minimize query response time, and maximize throughput without single point global coordination. The Data Cyclotron architecture [Goncalves and Kersten 2010] addresses this challenge using turbulent data movement through a storage ring built from distributed main memory and capitalizing on the functionality offered by modern remote-DMA network facilities. Queries assigned to individual nodes interact with the storage ring by picking up data fragments, which are continuously flowing around, that is, the hot set. The storage ring is steered by the Level Of Interest ( LOI ) attached to each data fragment, which represents the cumulative query interest as it passes around the ring multiple times. A fragment with LOI below a given threshold, inversely proportional to the ring load, is pulled out to free up resources. This threshold is dynamically adjusted in a fully distributed manner based on ring characteristics and locally observed query behavior. It optimizes resource utilization by keeping the average data access latency low. The approach is illustrated using an extensive and validated simulation study. The results underpin the fragment hot set management robustness in turbulent workload scenarios. A fully functional prototype of the proposed architecture has been implemented using modest extensions to MonetDB and runs within a multirack cluster equipped with Infiniband. Extensive experimentation using both microbenchmarks and high-volume workloads based on TPC-H demonstrates its feasibility. The Data Cyclotron architecture and experiments open a new vista for modern distributed database architectures with a plethora of new research challenges.

Modelling of Particle Deposition and Rebound Behaviour on Ventilation Ducting Wall Using an Improved Wall Model

This paper reports a study of particle deposition and rebound behaviour in a vertical two-dimensional ventilation duct, employing a Lagrangian particle model incorporating an algebraic rigid particle—wall impact model. A RNG κ - ε turbulence model was applied to solve the turbulent duct flow. Fifteen particle size groups ranging from 5 to 200 μm are investigated with one-way coupling approach. The turbulent airflow and particle movement were validated by experimental data. Adopting the particle—wall impact model, the dimensionless deposition velocities have been predicted smaller than those using conventional ‘‘trap’’ model, especially for particles of large relaxation time. The dimensionless deposition velocity and deposition fraction would first increase, and then decrease with increasing particle diameter. The deposition and capture fraction would roughly decrease with increasing frictional velocity. Additionally, Saffman force has played an important role in this improved wall model. This paper has demonstrated that particle rebound could have a considerable effect on the deposition and concentration of large particles in rooms and ventilation ducts. These findings would benefit the design of filters in ventilation systems and the control of particle contaminants that could affect the indoor air quality of the living spaces.

Two regime transitions to pseudo-homogeneous and heterogeneous bubble flow for various liquid viscosities

The gas hold-up variation and regime transition were investigated with different liquid viscosities ranging from 1.0 mPa s to 31.5 mPa s using a 0.15-m-in-diameter bubble column. In contrast to common observations, the gas hold-up graph with the superficial gas velocity could be categorized into three flow regimes: homogeneous, pseudo-homogeneous and heterogeneous flow regimes. The formation of large bubbles caused a transition from the homogeneous to the pseudo-homogenous flow regime, in which large bubbles rose vertically without oscillatory turbulence. According to the results from the dynamic gas disengagement (DGD) technique, large bubbles began to form at the transition superficial gas velocity to the pseudo-homogeneous flow regime. The transition to a heterogeneous flow regime was initiated by the turbulent movement of large bubbles. The transition superficial velocities to pseudo-homogeneous and heterogeneous flow regimes, u t1 and u t2, decreased with increasing liquid viscosity below a critical viscosity and converged to a certain value above that viscosity. However, the correlations from the literatures could not make a reasonable estimation of the transition superficial velocities because they did not consider the possible transition to a pseudo-homogeneous flow regime. Therefore, the two transition points should be predicted separately.

Robust Processing of Optical Flow of Fluids

This paper proposes a new approach, coupling physical models and image estimation techniques, for modelling the movement of fluids. The fluid flow is characterized by turbulent movement and dynamically changing patterns which poses challenges to existing optical flow estimation methods. The proposed methodology, which relies on Navier-Stokes equations, is used for processing fluid optical flow by using a succession of stages such as advection, diffusion and mass conservation. A robust diffusion step jointly considering the local data geometry and its statistics is embedded in the proposed framework. The diffusion kernel is Gaussian with the covariance matrix defined by the local second derivatives. Such an anisotropic kernel is able to implicitly detect changes in the vector field orientation and to diffuse accordingly. A new approach is developed for detecting fluid flow structures such as vortices. The proposed methodology is applied on artificially generated vector fields as well as on various image sequences.

Scaling properties of Navier-Stokes turbulence

The property of the velocity field and the cascade process of the fluid flow are key problems in turbulence research. This study presents the scaling property of the turbulent velocity field and a mathematical description of the cascade process, using the following methods: (1) a discussion of the general self-similarity and scaling invariance of fluid flow from the viewpoint of the physical mechanism of turbulent flow; (2) the development of the relationship between the scaling indices and the key parameters of the She and Leveque (SL) model in the inertial range; (3) an investigation of the basis of the fractal model and the multi-fractal model of turbulence; (4) a demonstration of the physical meaning of the flowing field scaling that is related to the real flowing vortex. The results illustrate that the SL model could be regarded as an approximate mathematical solution of Navier-Stokes (N-S) equations, and that the phenomena of normal scaling and anomalous scaling is the result of the mutual interactions among the physical factors of nonlinearity, dissipation, and dispersion. Finally, a simple turbulent movement conceptional description model is developed to show the local properties and the instantaneous properties of turbulence.

A mechanism of the activating effect of hydrodynamic cavitation on water

We have investigated the issue of water activation during turbulent movement of a liquid, this movement being characterized by disturbance of flow continuity (a cavitation mode). We have also studied the relationship between the stability of the metastable state of a liquid and introduced energy. Based on experimental data it was demonstrated that under action of effects of a hydrodynamic cavitation field hydroxylic radicals form in water. These radicals over time recombine with the formation of hydrogen peroxide or water molecules. Using a mathematical model we have proposed a mechanism for water activation and determined constants of the rate of chemical reactions.

Combined Effects of Passing Clouds and Wind Gusts on an Interactive Wind-PV System with Battery Storage Using Neural Networks

This article analyzes the combined effects of random clouds and wind gusts on a grid-linked rooftop wind-photovoltaic system (WPS) with battery storage. For short period intervals, the wind speed and the solar radiation are considered as the sole sources of power whose variations influence the system variables. The stochastic nature of gusty winds creates a quasi-permanent transitory environment for the wind power subsystem, where the wind generator voltage and power undergo steep changes in short periods of time. Likewise, passing clouds affect the variables of the photovoltaics. Since both subsystems have different dynamics, their respective responses are expected to impact differently the overall system behavior. The system responses are predicted with artificial neural networks (ANN). Unlike conventional modeling, the ANN simulation does not require the knowledge of system parameters. This allows circumventing two major problems: parameter uncertainty and system non-linearity, which could be high for large systems with multiple components placed in unpredictable environment characterized by turbulent movement of wind and random cloud passage. The dynamics of the system are captured and stored in the connection weights between two consecutive layers. The dispatchability of the battery-supported WPS as well as its stability and reliability during gusts and cloud passage are also discussed.

The turbulent characteristics of the gas–solid suspension in a square cyclone separator

Three-dimensional particle dynamics analyzer was employed to study the gas–solid flow in a square-shaped cyclone separator which was designed for large CFB application. Distribution of flow vector, fluctuating velocity, turbulent kinetic energy, turbulent intensity and particle concentration were discussed. The swirling flow inside the cyclone showed the Rankine vortex characteristics, i.e., strong swirling vortex at the central region of the cross-section and weak swirling quasi-free vortex near the wall. The quasi-laminar motion of particles enhanced the turbulent movement at the corners due to particle–particle/wall collision, which led to the local peak value of the turbulent kinetic energy and turbulent intensity. The corner is one of the major region to cause pressure drop because the suspension at the corners consumed more energy of the flow. The corners were found to be beneficial to particle separation mainly because the strong fluctuating flow consumed much of the kinetic energy of both the particle and the gas.

Two-dimensional wave-current interaction with a locally enriched quadtree grid system

Wave-induced currents may drive nearshore mixing and transport processes, including coastal pollutant dispersion, littoral drift, and long-term morphological changes through beach erosion and accretion. In this study, a numerical model is newly developed to simulate wave climate and localized currents in complicated coastal environments. The model developed is based on a quadtree grid system. The two-dimensional hydrodynamic governing equations are solved by using an explicit Adams-Bashforth finite difference scheme. Effects of wave breaking, shoaling, refraction, diffraction, wave-current interaction, set-up and set-down, turbulent mixing, bed friction, and shoreline movement are incorporated in the model. Results are presented for set-up at a beach in a flume due to normally incident waves, and longshore currents generated by oblique waves on a plane beach.

Importance of zooplankton for the persistence of a deep chlorophyll layer: A limnocorral experiment

A variety of interacting physical, chemical, and biological hypotheses have been proposed to explain the formation of deep chlorophyll layers (DCL). We used an experiment to test the importance of zooplankton grazing and nutrient transport as factors maintaining the DCL. In oligotrophic Yellow Belly Lake (Sawtooth Mountains, central Idaho), which has a DCL, we compared changes in the chlorophyll profiles in 17‐m‐deep limnocorrals with and without crustacean zooplankton. 15N ammonia and rhodamine dye were added to the epilimnion or metalimnion of the corrals to measure nutrient transport and diffusivity. In the limnocorrals with zooplankton, epilimnetic macrozooplankton biomass was 2× higher and estimated grazing rates were 1.8× higher than those in the metalimnion. After 11 d, chlorophyll levels in the zooplankton treatment declined 72% in the epilimnion but only 53% in the metalimnion, leading to the maintenance of the DCL. In the treatment without zooplankton, the epilimnetic chlorophyll increased 11% and the metalimnetic algal levels decreased 41%, resulting in the formation of an epilimnetic chlorophyll maxima. Biologically mediated movement of 15N from the epilimnion and metalimnion was downward, into either the metalimnion or the hypolimnion. Turbulent movement measured with rhodamine was high in the limnocorrals, and presumably 15N also moved into adjoining strata through this process. Grazing, however, coupled with a downward movement of nutrients via sedimentation into the lower strata appears to explain the persistence of the DCL.

Aviation Medicine and the Airline Passenger

If God meant us to fly, he would have given us feathers. Maybe he didn't because he cared about us and knew flying was dangerous. It's not as dangerous now as when Daedalus and Icarus tried out their wax wings or when the Montgolfier brothers' hot air balloon first rose into the air in 1783; but it is still dangerous. The first balloon flights tested man's ability to withstand a rare and hostile environment above the earth and it was fitting that one of the two people in the first balloon flight was a physician. We owe so much of our current understanding of the physiology of flight to these intrepid early physiologists and particularly to the 19th century French physiologist Paul Bert that it seems a pity that there is no chapter giving a historical perspective in Aviation Medicine and the Airline Passenger. Dr. Cummin and Professor Nicholson have assembled a distinguished list of contributors to share the medical wisdom accumulated from 99 years of powered flight. Would-be travellers are reminded that it is only a thin metal envelope that separates us from an outside temperature of -50°C and an oxygen partial pressure well below that needed to sustain life. Not even the aeroplane's skin shields us from galactic cosmic radiation which carries a small but not totally insignificant cancer risk of 0.002% for each transatlantic crossing, so that regular flyers are exposed to doses of radiation above that of most classified radiation workers. The theoretical lifetime risk of a commercial pilot being killed by cosmic radiation is twice that of death from a flying accident. Inside the cabin we are exposed to the risks of leaking neurotoxic lubricants, infectious disease and air-rage from fellow passengers. The ever-present sick bag in our seat pocket reminds us of the effect of turbulent movement on the vestibular apparatus, and after a long easterly flight when we step safely onto the tarmac our bewildered brains take 4 days to regain their vigilance and sleep pattern. These and other aspects of flying are well described and make good reading. The bulk of the book, however, deals with more practical considerations on the management of medical conditions before and during flight. The simple messages stand out. Exhort your patients to stop smoking 48 hours before their flight. Tell them to put all medicines in their cabin luggage, not in the hold, and give them a written summary detailing their condition and treatment. If they are on warfarin they should carry ampoules of vitamin K, and if in a wheelchair a repair kit and pump. Make sure scuba divers do not fly for 48 hours after diving. If confronted with any medical condition on the plane, take a careful history. If necessary look through the patient's hand luggage for evidence of their disease and medication. Take heed of the excellent chapter by Geoffrey Chamberlain which tactfully reminds the well-meaning doctor that the less the amateur accoucheur does the better: mother, baby and well-trained stewardess know best. In case of pneumothorax this book tells all, including how to turn the finger of a rubber glove into a one-way valve. However, I shall worry much more about the person sleeping next to me who just could have had a silent cardiac arrest. The first chapter is on medicolegal aspects. Certainly it is relevant, but also depressing, dwelling as it does on such issues as the need to seek from the captain contractual indemnity for any ‘Good Samaritan’ act carried out before leaving the aircraft. No doubt good advice, but there is no mention of this in the original story of the Good Samaritan. Some of the chapters and particularly the chapter on immunization and infectious disease mix aviation medicine with travel medicine. This may be an asset—two books for the price of one (and some compensation for the £65 price tab). Each chapter is self-contained, which has the disadvantage that we are told frequently, for example, the relation between altitude and gas partial pressure but the advantage that only one chapter needs to be consulted to obtain the information needed for a particular patient. For the general practitioner this is an authoritative source from which to guide the ageing but still travel-hungry and sun-seeking patient and the book will fit best here in the GP's practice library. For the occupational physician who advises frequent fliers it is a must, and it will be a very useful reference for hospital libraries and to all those professionally involved in aviation medicine both commercial and military. In the next edition it would be nice to have that enriching chapter on the history of aviation medicine and more didactic bullet points at the end of each chapter; and perhaps we might have a cheaper paperback version.

ACCUMULATION AND DISTRIBUTION OF Pb, Cu, Zn AND Cd IN SUNFLOWER (Helianthus annuus L.) GROWN IN AN INDUSTRIALLY POLLUTED REGION / ACUMULACION Y DISTRIBUCION DE Pb, Cu, Zn Y Cd EN EL GIRASOL (Helianthus annuus L.) CULTIVADO EN LA REGION INDUSTRIALMENTE POLUCIONADA / ACCUMULATION ET DISTRIBUTION DE Pb, Zn ET DE Cd DANS LE TOURNESOL (Helianthus annuus L.) CULTIVÉ DANS

SUMMARYInvestigations conducted during last years showed serious violations of ecological equilibrium in many agricultural regions.Crops produced in these regions are commonly used as food and feed. It has been established that the content of heavy metals in the soils and agricultural crops grown nearby the metallurgical factories is much above the admissible concentration. Micro-particles of Pb, Cu, Zn and Cd separated in the atmosphere by aerosols, accumulate in the soil, plants and water areas. From the studied heavy metals the coarse particles of Zn commonly pile in soil nearby the contaminator, and the heavier particles of Pb are distributed by the prevailing winds. These elements accumulate shallow in the upper layer and confined to quantity move down. The irregular contamination of soil around certain factory is in great part dependent on turbulent movement of air, windlessness and the condition of fluctuating atmosphere - inversion. Contamination with heavy metals is most oftenly in according with areas. Maximum accumulation is found out on boundary areas in a distance at about 1000 m from the factory called the area of accumulation, and 15 000 m away from the factory called area of distraction. Commonly, on this area is grown one of the specific for Bulgaria culture - the sunflower. This needs solving of many problems connected with studying the accumulation and depous of localization of heavy metals in sunflower grown on contaminated soil, as well as their influence upon soil fertility.

Disturbance‐related heterogeneity in the seed banks of a marine angiosperm

Summary 1 Patterns in the distribution of seeds of the marine angiosperm Halodule uninervis were described over spatial scales ranging from a few centimetres to meadows separated by more than 120 km along the north‐eastern coast of Queensland, Australia. Separate surveys examined how seed bank densities were related to: (i) the distribution of male and female plants (primary dispersal) and (ii) disturbances caused by turbulent water movement and the foraging of large marine vertebrates. 2 The distribution of seeds was extremely heterogeneous at very small scales of sampling (centimetres to tens of centimetres). Variation in seed abundance within individual meadows (87% of total variation in seed densities) was at least an order of magnitude greater than that among separate intertidal populations (13%). Densities of seeds were greatest in micro‐topographic depressions where the overlying vegetation had been removed by directional water currents and the feeding activities of dugongs. Smaller disturbances that did not disrupt the cover of vegetation had no effect on seed abundance. Detailed mapping of the distributions of seeds and male and female reproductive shoots showed only a weak relationship between primary seed production and the seed bank, but revealed a pattern of seed distribution that was consistent with accumulation in linear depressions in the meadow. 3 The seed banks of intertidal sediments exhibit many similarities to those of physically dynamic desert sands. In these unstable environments, seeds are most abundant in sheltered micro‐habitats where sediment mobility is impeded. Plants that inhabit desert and marine sands appear to have responded similarly to strong selective pressures on seedling recruitment by developing mechanisms that restrict primary seed dispersal to take advantage of micro‐sites provided by established plants.

Effective depth of fresh air distribution in rooms with single-sided natural ventilation

This paper introduces the effective depth of fresh air distribution in rooms with single-sided natural ventilation. A numerical method for the determination of the effective depth is described. The numerical method is based on the CFD technique involving the governing equations for air flow and the transport equation for the local mean age of air. The renormalisation group k− ε model of turbulence is used with equations for the conservation of mass, momentum and energy to predict turbulent buoyancy-induced room air movement. The air flow through a large opening is derived from the Bernoulli theory. The predicted air flow pattern, air temperature and local mean age of air are used to determine the effective depth of fresh air distribution in a naturally ventilated room with a window opening for summer cooling. It is shown that the effective depth for thermal comfort may not coincide with that for air quality and in summer, the requirement for thermal comfort is the limiting factor to the effective room depth. The effects of window opening levels and room heat gains on the air flow rate and effective depth are investigated.

Phytoplankton development and turbulent mixing in Lake Kinneret (1992–1996)

We have utilized data from a recently developed three-dimensional velocity fluctuation meter to compute the dissipation of turbulent kinetic energies (TKE) and the intensity of turbulent mixing in horizontal and vertical planes in the pelagic, epilimnic water of Lake Kinneret, Israel. These characteristics of wind-induced turbulent movement have been monitored from January 1992 through December 1996. The turbulence parameters were strongly correlated to wind energy inputs, calcu- lated daily as 5 day cumulative inputs. There have been dramatic changes in the annual and seasonal development of phytoplankton, together with unusually high levels of primary production in this lake since 1994. We observed different patterns of vertical and horizontal turbulent movement and of TKE dissipation rates during the years when 'unusual' phytoplankton development occurred (1994-1996) compared to 'normal' years (1992, 1993). The first appearance of the filamentous cyanobacterium Aphanizomenon in this lake in August-September 1994 coincided with a period of markedly lower rates of TKE dispersion and a shift from vertical to horizontal dominance of the turbulent eddy spins. The absence of a regular winter-spring bloom of the dinoflagellate, Peridinium, in 1996 occurred when dissipation rates of TKE were extremely high, while record high amounts of dinoflagellates (1994, 1995) appeared when dissipation rates were very low. Correlations were shown between phyto- plankton parameters (chlorophyll, primary production and the ratio of primary production to chloro- phyll) and both the dissipation rate of TKE and the intensity of water turbulent mixing in the vertical plane. We suggest that the changes in the 'turbulence climate' of Lake Kinneret were an important factor in determining shifts in phytoplankton succession and the population composition of the algal assemblage.