INFLUENCE OF THE MORPHOLOGICAL AND HYDRAULIC CHARACTERISTICS OF MOUNTAIN STREAMS ON FISH HABITAT SUITABILITY CURVES

Microhabitat preferences of adult brown trout (Salmo trutta m. fario) were monitored for the purpose of determining design parameters for river restoration. The habitat preferences were evaluated during the summer period of minimum flows. Since 1995, field measurements have been performed in 52 reaches in 43 mountain and piedmont streams. The relationship between hydraulic characteristics and the values of maximum habitat suitability derived from velocity and depth habitat suitability curves (HSCs) was statistically determined. Trout in natural stream reaches showed a strong degree of dependence on depths, but in regulated streams, they were dependent on velocities. The representative habitat suitability curves for four depth intervals were extrapolated. From these outputs, the optimum depths of a microhabitat for river restoration measures and/or assessment of the influence of water withdrawals can be derived. The influence of geological regions on the shape of HSCs has not been proved; therefore, it is conceivable that after verification, the generalized HSCs may also be valid in other mountain and piedmont regions. Copyright © 2011 John Wiley & Sons, Ltd.     

BOOTSTRAP SAMPLING IS WITH REPLACEMENT: A COMMENT ON AYLLÓN ET AL. (2011)

The bootstrap can be used to estimate confidence intervals for complex statistics such as weighted usable area, the habitat index calculated by the Physical Habitat Simulation System (PHABSIM) and related models. Use of the bootstrap entails sampling with replacement from the original sample, such as a set of PHABSIM transects. Because the method has been improperly applied to PHABSIM transects in several instances, I explain in detail why bootstrap sampling is with replacement. Copyright © 2011 John Wiley & Sons, Ltd.     

History and review of the habitat suitability criteria curve in applied aquatic ecology

Hydraulic microhabitat assessment is a category of environmental flow tools (e.g., Physical Habitat Simulation system and other methodologically similar software) that, at its core, uses habitat suitability criteria (HSC) to link values of point hydraulic variables (usually depth, velocity, and substrate/cover) to habitat values for target life stages. Although this assessment tool has been used worldwide for decades, the history of the HSC curve is relatively unknown because the foundational information is predominantly contained in obscure and often unpublished reports. We review the history of the HSC concept in applied aquatic ecology to clarify its scientific pedigree, ensure its proper use, and build a foundation for future research. We begin the review with the formative decades of the 1950's through the 1970's, when consumptive‐based western USA water law conflicted with conservation traditions and natural resource management objectives, although water allocation issues date back at least to the 19th century. By analysing the history of the HSC concept, we aim to establish the biological, hydrologic, and geomorphological conditions that must be met for the HSC concept to be successfully employed. In spite of its documented assumptions and limitations, the HSC concept will likely continue to be a useful tool to help address water resources allocation issues in defined hydrologic and geomorphic settings. We conclude that HSC‐based methodologies should be considered as one of several environmental flow approaches involved in sustainable water resources management.     

Interactive effects of cover and hydraulics on brown trout habitat selection patterns

Habitat modelling results are extremely sensitive to the habitat suitability criteria (HSC) used in the simulations. HSCs are usually expressed as univariate habitat suitability curves, although such univariate approach has been long questioned, since overlooking interactions between hydraulic variables may misrepresent the complexity of fish behaviour in habitat selection. It could lead to adopt erroneous flow management decisions based on misleading results. Furthermore, the interactive effects of hydraulic variables on habitat selection may be driven by the structural features of the channel, which determine cover availability. Therefore, we compared brown trout habitat selection patterns through multivariate resource selection functions (RSFs) in structurally contrasting rivers to unveil the interactive effects of hydraulics and cover elements and their consequences in univariate HSC results. Microhabitat preferences of young‐of‐the‐year (0+) trout were similar across fast and slow waters, meanwhile juvenile (1+) and adult (>1+) preferences significantly changed. RSFs for young‐of‐the‐year trout were consistent with univariate results and did not differ among water types. However, RSFs for older trout varied among water types and revealed complex interactions among hydraulic variables and between hydraulics and structural elements, which were not described accurately by univariate curves. Therefore, results suggest that interactions between water depth and current velocity have a significant effect on habitat selection patterns in juvenile and adult brown trout, this effect being controlled by cover availability. Copyright © 2008 John Wiley & Sons, Ltd.     

INFLUENCE OF INCLINATION ANGLE ON THE MOTION OF TAYLOR BUBBLES IN UPWARD SLUG FLOW

1 .　ＩＮＴＲＯＤＵＣＴＩＯＮＳｌｕｇｆｌｏｗｉｓｏｎｅｏｆｔｈｅｍｏｓｔｃｏｍｐｌｉｃａｔｅｄｆｌｏｗｐａｔｔｅｒｎｓａｎｄｏｃｃｕｒｓｏｖｅｒａｗｉｄｅｒａｎｇｅｏｆｇａｓａｎｄｌｉｑｕｉｄｆｌｏｗｒａｔｅｓｉｎｓｍａｌｌａｎｄｍｅｄｉｕｍｓｉｚｅｔｕｂｅｓ .Ｉｔｉｓｃｈａｒａｃｔｅｒｉｚｅｄｂｙｌａｒｇｅｂｕｌｌｅｔ ｓｈａｐｅｂｕｂｂｌｅｓ (ｒｅ ｆｅｒｒｅｄｔｏａｓｔｈｅＴａｙｌｏｒｂｕｂｂｌｅｓ) ,ａｌｍｏｓｔｆｉｌｌｉｎｇｔｈｅｔｕｂｅ ,ｗｈｉｃｈａｒｅｓｅｐａｒａｔｅｄｂｙｌｉｑｕｉ…     

THE INFLUENCE OF THE SECONDARY NORMAL STRESS DIFFERENCE OF VISCOELASTIC FLUID ON ECCENTRIC CAPSULE FLOW

ＴＨＥＩＮＦＬＵＥＮＣＥＯＦＴＨＥＳＥＣＯＮＤＡＲＹＮＯＲＭＡＬＳＴＲＥＳＳＤＩＦＦＥＲＥＮＣＥＯＦＶＩＳＣＯＥＬＡＳＴＩＣＦＬＵＩＤＯＮＥＣＣＥＮＴＲＩＣＣＡＰＳＵＬＥＦＬＯＷ￥ＰａｎＤａ－ｌｉｎ（ＧｕａｎｇｄｏｎｇＩｎｓｔｉｔｕｔｅｏｆｏｆＴｅｃ...     

INFLUENCE OF LONG AND DEEPLY-BURIED DIVERSION TUNNELS ON THE WATER TEMPERATURE

A 3-D temperature model for diversion tunnel was developed by combining/e-e model and energy transport equation. The actual geometry data of the tunnel was used to construct a three-dimensional computational domain including the concrete lining. As the interaction between temperature and velocity fields can be taken into account, the model can be employed to accurately simulate the temperature and velocity field. The model was validated with the field data observed in the diversion tunnel of the Nanya River. The water temperature of the diversion tunnel of the Second Jinping Cascade Hydropower Station to be built was predicted. It is shown that the temperature increase is not observable due to the large diameter of the tunnel, the big flow rate and the short contact time. The result can provide scientific foundation or reference for the design of hydropower station, and protection strategy of aquatic organisms and aquatic ecosystem.     

INVESTIGATION OF INFLUENCE OF WETTABILITY ON POISEUILLE FLOW VIA MOLECULAR DYNAMICS SIMULATION

In this article, the influence of wettability on a liquid flow between two parallel plane walls were studied by using Non-Equilibrium Molecular Dynamics (NEMD) simulation. The wettability of the solid surfaces can be described as the contact angle. The liquid flow rate, the slip velocity and the slip length which are affected by the contact angle were investigated. The results show that the boundary condition at a microscopic level is different from a “no-slip” condition at a macroscopic level. There exits a slippage of a liquid flow for the hydrophobic boundary and an external force is needed to overcome threshold pressure for the hydrophilic boundary. And the orderly layered distributions of the liquid particles near the hydrophilic surface vary from a place near the hydrophobic surface. The study indicates that the surface wettability plays a significant role on possibilities of forming a viscous layer and the direct slip at the solid surface. The resistance of liquid flow can be decreased by changing the wettability of boundary surface.     

THE INFLUENCE OF DIFFERENT DESIGN PARAMETERS AND WORKING CONDITIONS ON CHARACTERISTICS OF HEAT METERS

In this article,the UDF technology in Fluent software is used to simulate three-dimensional flow fields and to obtain various flow parameters. The standard k-ε model and the RNG k-ε model are both used to calculate the inner flow field of the basal meter,and a comparison of the calculated results between two models shows that RNG k-ε model is more effective for calculations of the inner flow of rotary wing mechanism. The influence of tip clearance on the characteristics of the basal meter is studied. The in...     

Effect of flow‐related substrate alteration on physical habitat: a case study of the endemic river loach Sinogastromyzon puliensis (Cypriniformes,Homalopteridae) downstream of Chi‐Chi Diversion Weir,Chou‐Shui Creek,Taiwan

This paper addresses the variation of substrate status with flow in the framework of habitat simulation. The Physical Habitat Simulation System (PHABSIM) was developed as a tool for water management and has become one of the most popular methods worldwide. Despite its many advantages, the variation of channel properties with flow is not addressed in PHABSIM. We modified PHABSIM by incorporating a sub‐program that can perform substrate analyses under five different schemes for evaluating the substrate suitability. These schemes include the conventional methods to specify the substrate attribute (scheme 1) and to use the mean grain size of the original bed material for determining the substrate suitability (scheme 2), or employ the threshold conditions for sediment entrainment to evaluate the nominal grain size of the stable substrate (schemes 3–5). As a case study, Sinogastromyzon puliensis in Chou‐Shui Creek (Taiwan) is selected as the target species for the habitat simulation. For schemes 1 and 2, the substrate attribute specified for each cell of a cross‐section does not change with flow. The nominal grain size of the stable armour material (scheme 5) is generally greater than the nominal grain sizes of the above‐critical bed material (scheme 3) and the static armour layer (scheme 4). The simulation results indicate that the suitability values specified in scheme 1 and the resulting habitat area are on the optimistic side, whereas scheme 2 tends to undervalue the suitability of the hydraulically worked substrate. The overall variation trends of the weighted usable area (or percentage usable area) curves for different substrate schemes are similar, especially in the in‐phase regions of the water velocity and depth. The results of this study appear to imply that the flow‐related habitat analyses are not usually sensitive to substrate. Copyright © 2002 John Wiley & Sons, Ltd.     

NUMERICAL ANALYSIS OF THE INFLUENCE OF THE TIP CLEARANCE FLOWS ON THE UNSTEADY CAVITATING FLOWS IN A THREE- D IMENSIONAL INDUCER

To clarify the influences of the tip clearance flows on the unsteady cavitating flow,the three-dimensional unsteady cavitating flows through both the two-dimensional cascades and the three-dimensional inducer with and without tip clearance are performed numerically.The governing equations for the compressible fluid flow with the DES turbulence model are employed with the assumption of the isentropic process of liquid phase.The evolution of cavities is represented as the source/sink of vapor phase.The basic equations in the curve linear coordinate are solved by the finite difference method.As the results of the three-dimensional cavitating flows through the two-dimensional cascades,the tip clearance flows from the pressure side to the suction side of the blade produces the tip vortex cavitation,which affects the sheet cavitation on the leading edge of the next blade and enhances the blockage effect near the casing than the flows without tip clearance.On the other hand,in the case of the three-dimensional inducer,the large backflow cavitation is observed around the inlet of the inducer,where the cavities are developed on the casing by the tip clearance flows.The large pressure gradient between the non-cavitating pressure side and the cavitating suction side enhances the tip clearance flows.The calculation considering the tip clearance reproduces the developed cavitation region similar to that of experimental visualizations.Additionally,the backflow cavitation rotates with the speed slower than the rotation speed of the inducer.Then,the rotation of backflow cavitation causes the periodic fluctuation of the outlet pressure greater than that of the inlet pressure.     

NUMERICAL SIMULATION OF THE EFFECT OF FILLET FORMS ON APPENDAGE－BODY JUNCTION FLOW

ＮＵＭＥＲＩＣＡＬＳＩＭＵＬＡＴＩＯＮＯＦＴＨＥＥＦＦＥＣＴＯＦＦＩＬＬＥＴＦＯＲＭＳＯＮＡＰＰＥＮＤＡＧＥ－ＢＯＤＹＪＵＮＣＴＩＯＮＦＬＯＷＬｉＤｉｎｇ；ＺｈｏｕＬｉａｎ－ｄｉ（ＣｈｉｎａＳｈｉｐＳｃｉｅｎｔｉｆｉｃＲｅｓｅａｒｃｈＣｅｎｔｅｒＰ．...     

MODELLING THE EFFECTS OF RIVER FLOW ON POPULATION DYNAMICS OF PIPING PLOVERS (CHARADRIUS MELODUS) AND LEAST TERNS (STERNULA ANTILLARUM) NESTING ON THE MISSOURI RIVER

Reservoir management on the Missouri River has changed the flow regime that once created dynamic emergent sandbar habitat (ESH) for the interior least tern (Sternula antillarum) and piping plover (Charadrius melodus). High flows that create large amounts of ESH are now rare, but the remaining interannual variability in river stage has strong effects on the amount of ESH available for nesting shorebirds. The scarcity of habitat has led the United States Army Corps of Engineers to develop an adaptive management plan for the restoration of ESH to support nesting terns and plovers. We describe the stochastic simulation models of ESH, plover populations and tern populations used in the adaptive management process, and examine the effects of river flow on projected outcomes of habitat restoration. The population models are most sensitive to uncertainty in adult survival rates. Model validation against historical amounts of ESH and population sizes suggests the model is a reasonable predictor of future dynamics. Flow variability contributes as much uncertainty as parameter estimation error to plover model projections but negligible uncertainty to the tern model. Autocorrelation in flow between years has stronger effects on population outcomes than the intensity of habitat restoration effort does. We compared population outcomes after a habitat‐creating flow with population outcomes following habitat restoration and found that large pulses of habitat creation produced similar or better outcomes in the short term than low but consistent habitat restoration. However, bird populations fared better in the long term with low levels of restoration when habitat‐forming flows were rare. Copyright © 2013 John Wiley & Sons, Ltd.     

RESEARCH ON THE FLOW PROPERTY IN THREE DIMENSIONAL CAVITY OF MICRO-CHANNEL

1. INTRODUCTIONOver the past decade , many attentions havebeen paid to the liquid flowin microchannels dueto the development in microfluidic devices and sys-tems .The separation and mixing of the fluidin mi-crochannels have special characteristics[1]. The re-search of liquid-liquid extraction technique basedon the microfluidic chip is an i mportant aspect inthe field of microfluidic chip analysis . Comparedwith the traditional liquid-liquid extraction tech-nique , the micromation of extra…     

THE NATURAL CONVECTION OF AQUIFERS WITH CONSTANT HEAT SOURCES AND ITS INFLUENCE ON TEMPERATURE FIELDS

By combining sand tank tests with numerical simulations, this paper studies the temperature fields around constant heat sources to reveal the mechanism of the natural convection and its influence on the temperature fields in the process of energy storage. Using the "24-channel temperature auto acquisition system" developed by our research group in the tests, the temperatures are recorded at measuring points within the research area in the tests, the revised Brinkman equation and a transfer-convection balance model are used for solving the aquifer water-thermal coupling problems, and through comparison of the test results with the calcula- tion results, it is discovered that the influence ranges and the variations of the two temperature fields are consistent, which validates the mathematical model. On the basis of this, we also study the influences of the heat source positions and the boundary conditions on the temperature fields, and the results show that, under the natural convection, the heat source positions may influence the distri- bution of the temperature fields, thus affect the energy storage. For the same energy storage layer, the temperature field for the top energy storage is characterized by a smaller heat influence range and a relatively concentrated temperature distribution. However, when the heat source is at the bottom, the range of a temperature field, and the temperature is relatively dispersed, which is not favorable to heat recycle, with the same heat source position, the boundary conditions determine the size of the critical Rayleigh number, and thus have an influence on the occurrence and the strength of the natural convection, and accordingly, on the temperature fields.     

NUMERICAL SIMULATION OF ATOMIZATION RAINFALL AND THE GENERATED FLOW ON A SLOPE

This article studies the atomization rainfall and the generated flow on a slope by numerical simulations.The atomization rainfall is simulated by a unified model for splash droplets and a suspended mist,and the distribution of the diameter of splash rain drops is analyzed.The slope runoff generated by the atomization rainfall is simulated by a depth-averaged 2-D model,and the localization of the rainfall intensity in space is specially considered.The simulation results show that:(1) the median rain size of the atomization rainfall increases in the longitudinal direction at first,then monotonously decreases,and the maximum value is taken at the longitudinal position not in consistent with the position where the maximum rain intensity is taken.In the lateral direction the median rain size monotonously decreases,(2) since the atomization rainfall is distributed in a strongly localized area,it takes a longer time for its runoff yield to reach a steady state than that in the natural rainfall,the variation ranges of the water depth and the velocity in the longitudinal and lateral directions are larger than those in the natural rainfall.     

SIMULATION OF THE TWO PHASE FLOW OF DROPLET IMPINGEMENT ON LIQUID FILM BY THE LATTICE BOLTZMANN METHOD

A Lattice Boltzmann Method (LBM) with two-distribution functions is employed for simulating the two-phase flow induced by a liquid droplet impinging onto the film of the same liquid on solid surface.The model is suitable for solution of twophase flow problem at high density and viscosity ratios of liquid to vapor and phase transition between liquid and its vapor.The roles of the vapor flow,the density ratio of liquid to vapor and the surface tension of the droplet in the splashing formation are discussed.It is concluded that the vapour flow induced by the droplet fall and splash in the whole impinging process may affect remarkably the splash behaviour.For the case of large density ratio of liquid to vapor a crown may engender after the droplet collides with the film.However,for the case of small density ratio of liquid to vapor a "bell" like splash may be observed.     

RESEARCH ON THE MOTION CHARACTERISTICS OF FIBER SUSPENSIONS IN A WEDGE-SHAPED FLOW

1.　INTRODUCTIONTheliquidorgasflowofsolidfibersuspensionsconcernssomediffcultproblemsinthetheoreticalresearchofmultiphaseflowandNon-Newtonianflow.Sotheresearchofithasgreattheoreticalvalues.Atthesametime,theapplicationoftheflowwithfibersuspensionsisveryextensive.Inmaterialsscience,compositematerialsarebeingpaidmoreandmoreattentiontoshort-fibermaterialarethemostcommononeinvariouscompositematerials.Themoldingandmachiningofshort-fibermaterialhavemuchtodowiththedynamiccharacteristicsoftheflow…     

PARAMETRIC STUDY ON THE THRUST OF BUBBLY WATER RAMJET WITH A CONVERGING-DIVERGING NOZZLE

To predict the thrust of bubbly water ramjet with a converging-diverging nozzle, the physical processes occurring in the diffuser, mixing chamber and nozzle were analyzed. The mathematical models were constructed separately under the restrictions of certain assumptions. The bubbly nozzle flow was examined using a two-fluid model and accomplished by specifying the water velocity distribution in the nozzle. The numerical analysis of flow field in the nozzle shows that the Mach number at the throat is 1.009, near unity, and supersonic bubble flow appears behind the throat. There is greater thrust produced by bubbly water ramjet, compared with single-phase air ramjets. Subsequently, the influences of vessel velocity, air mass flow rate, inlet area A_m, area ratio (i.e., mixing chamber to inlet area A_m/A_i), and initial bubble radius on the thrust were emphatically investigated. Results indicate that the thrust increases with the increase of air mass flow rate, inlet area and the area ratio, and the decrease of initial bubble radius. However, the thrust weakly depends on the vessel velocity. These analytical and numerical results are useful for further investigation of bubbly water ramjet engine.     

ASSESSING THE IMPACTS OF RIVER REGULATION ON NATIVE BULL TROUT (SALVELINUS CONFLUENTUS) AND WESTSLOPE CUTTHROAT TROUT (ONCORHYNCHUS CLARKII LEWISI) HABITATS IN THE UPPER FLATHEAD RIVER,MONTANA, USA

Hungry Horse Dam on the South Fork Flathead River, Montana, USA, has modified the natural flow regimen for power generation, flood risk management and flow augmentation for anadromous fish recovery in the Columbia River. Concern over the detrimental effects of dam operations on native resident fishes prompted research to quantify the impacts of alternative flow management strategies on threatened bull trout (Salvelinus confluentus) and westslope cutthroat trout (Oncorhynchus clarkii lewisi) habitats. Seasonal and life‐stage specific habitat suitability criteria were combined with a two‐dimensional hydrodynamic habitat model to assess discharge effects on usable habitats. Telemetry data used to construct seasonal habitat suitability curves revealed that subadult (fish that emigrated from natal streams to the river system) bull trout move to shallow, low‐velocity shoreline areas at night, which are most sensitive to flow fluctuations. Habitat time series analyses comparing the natural flow regimen (predam, 1929–1952) with five postdam flow management strategies (1953–2008) show that the natural flow conditions optimize the critical bull trout habitats and that the current strategy best resembles the natural flow conditions of all postdam periods. Late summer flow augmentation for anadromous fish recovery, however, produces higher discharges than predam conditions, which reduces the availability of usable habitat during this critical growing season. Our results suggest that past flow management policies that created sporadic streamflow fluctuations were likely detrimental to resident salmonids and that natural flow management strategies will likely improve the chances of protecting key ecosystem processes and help to maintain and restore threatened bull trout and westslope cutthroat trout populations in the upper Columbia River Basin. Copyright © 2011 John Wiley & Sons, Ltd.