Showing papers on "Water flow published in 1971"

The production of turbulence near a smooth wall in a turbulent boundary layer

Abstract: The structure of the flat plate incompressible smooth-surface boundary layer in a low-speed water flow is examined using hydrogen-bubble measurements and also hot-wire measurements with dye visualization. Particular emphasis is placed on the details of the process of turbulence production near the wall. In the zone 0 < y+ < 100, the data show that essentially all turbulence production occurs during intermittent ‘bursting’ periods. ‘Bursts’ are described in some detail.The uncertainties in the bubble data are large, but they have the distinct advantage of providing velocity profiles as a function of time and the time sequences of events. These data show that the velocity profiles during bursting periods assume a shape which is qualitatively distinct from the well-known mean profiles. The observations are also used as the basis for a discussion of possible appropriate mathematical models for turbulence production.

Water flow and gas exchange at the gills of rainbow trout, Salmo gairdneri.

Abstract: 1. Ventilation volume was measured directly in rainbow trout using a rubber membrane attached to the mouth which separated inspired and expired water and allowed collection of the latter. 2. Mean ventilation volume at 8.6 °C for 18 trout weighing approximately 200 g was 37±1.8 ml/min/fish. Mean ventilation rate and ventilatory stroke volume averaged 74 breaths/min and 0.5 ml/breath respectively. 3. Ventilation volume could be increased nearly sevenfold during moderate, shortterm hypoxia as a result of a large increase in ventilatory stroke volume and a small increase in ventilation rate. 4. The ratio between the flow rates of water and blood through the gills was approximately 10. 5. Percentage utilization of oxygen from inspired water had a mean of 46±1.5% and ranged from 23 to 64%. 6. Artificial perfusion of the gills with water at different flow rates was achieved by tying a tube into the mouth of trout. 7. Perfused fish could not saturate their arterial blood with oxygen at a perfusion rate of 45 ml/min but could do so at rates ranging from 85 to 1200 ml/min. 8. Low arterial tensions at a perfusion rate approximating the mean V·G of fish with oral membranes are probably the result of a poor pattern of water flow over the gills during perfusion. 9. Opercular movements occurred only at perfusion rates below 700 ml/min and increased in frequency as perfusion rate dropped. This ventilatory activity may have resulted from receptors sensitive either to water flow over the gills or to arterial Po2. 10. As perfusion rate went up cardiac output and oxygen uptake increased. These changes were accompanied by a drop in dorsal aortic pressure which reflected vasodilation of the gills and peripheral circulation. This change in the pattern of blood flow through the gills contributed to a 50% increase in oxygen transfer factor across the gills. 11. At the highest perfusion rates there was no apparent impairment of gas exchange even though anatomical deadspace was probably high.

Mechanics of Sheet Flow under Simulated Rainfall

Abstract: Friction factors are presented for spatially varied sheet flow with rainfall on a hydraulically smooth surface as obtained from both surface profile and hot film surface probe measurements. The results are presented in the form f = C /R, in which C increases with rainfall intensity and surface slope. A two-part velocity profile mathematical model based on von Karman's similarity hypothesis is presented and correlated with hot film measurements. Relative longitudinal turbulence intensity profiles with rainfall are characterized by a sharp increase in relative intensity near the surface and a general increase throughout the depth with increasing rainfall. Turbulent energy spectral analyses indicate that the rainfall causes a shift of the energy content to higher frequencies than for the case of uniform flow at the same Reynolds number.

Water, heat and crop growth

Abstract: Water, heat and crop growth , Water, heat and crop growth , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی

Nutrients in Streams Draining Woodland and Farmland near Coshocton, Ohio

Abstract: Nitrogen, phosphate, and potassium concentrations were measured in streams draining woodland and farmland watersheds at Coshocton, Ohio, 1966 through 1969. Temporal variations in the nutrient concentrations were much smaller than the changes in the rate of streamflow. No relationship was found between any nutrient concentration and streamflow, and no seasonal changes in concentration were detected. Nutrient losses from farmland were significantly greater than those from woodland. The nitrate-N concentration in the farm runoff was below 2 ppm except for one short period when it rose to 10 ppm. The input of nitrogen in the rain was greater than the loss in runoff from both watersheds. The average concentration of phosphate in runoff was 22 ppb (of P) from the farm and 15 ppb from the woodland. The analysis of the data shows that total nutrient losses cannot be calculated meaningfully unless both hydrologic and chemical data are available. The volume of water flow is the most important variable in this calculation.

An experimental investigation of pulsating turbulent water flow in a tube

Abstract: Experiments were made on a pulsating water flow at a mean flow Reynolds number of 3770 in a cylindrical tube of diameter 3·81 cm. Pulsations were produced by a piston oscillating in simple harmonic motion with a period of 12 s. Turbulence was made visible by means of a sheet of dye produced by electrolysis from a fine wire stretched across a diameter. The sheet of dye is contorted by the turbulent eddies, and cine-photography was used to find the velocity of convection which was shown to be the flow speed except in certain circumstances which are discussed. By subtracting the mean flow velocity profile the profile of the component of the motion oscillating at the imposed frequency was determined.The Reynolds number of these experiments lies in the turbulent transition range, so that large effects of laminarization are observed. In the turbulent phase, the velocity profile was found to possess a central plateau as does the laminar oscillating profile. The level and radial extent of this were little different from the laminar ones. Near to the wall, the turbulent oscillating profile is well represented by the mean velocity power law relationship, u/U ∝ (y/a)1/n. In the laminarized phase, the turbulent intensity is considerably reduced at this Reynolds number. The velocity profile for the whole flow (mean plus oscillating) relaxes towards the laminar profile. Laminarization contributes appreciably to the oscillating component.Extrapolation of the results to higher Reynolds numbers and different frequencies of oscillation is suggested.

Initiation of Ripples on Flat Sediment Beds

Abstract: For natural sands under turbulent water flow, ripples are found to form on a flat bed from small deformations caused by the random action of high turbulent velocities close to the bed. The deformations affect the grain movement pattern so as to form a bed disturbance or collection of grains that induce a separation eddy to form. The height of such a disturbance was found to be of the order of two or three grain diameters, and a height-to-length ratio of the order of 1 to 100. Sands with median diameters of 137 micron and 495 micron were used in the experiments. The definition of initial movement of fine sediment established by Grass, was extended by these experiments to define the critical conditions for the initiation of ripples from a flat bed. Additional experiments were made in which the grain Reynolds Number was varied by varying the temperature and thus the viscosity of the water. The results suggested that the described mechanism of ripple formation does not operate for grains larger than 600 micron at normal temperatures.

Sodium chloride absorption and solute‐linked water flow across the epithelium of the coprodeum and large intestine in the normal and dehydrated fowl (Gallus domesticus). In vivo perfusion studies

Abstract: 1. The transmural net flow of salt and water in the coprodeum and large intestine of normal and dehydrated hens was investigated by means of an intraluminal in vivo perfusion technique. The lumen was perfused with hypo-, iso-, and hyperosmotic salt solutions. Polyethylene glycol (PEG 4000) and [(14)C]inulin served as water markers.2. The maximal net Na(+) flow (J(Na)) from the mucosal to the serosal side was nearly the same in the two states of hydration: normal birds 308 mu-equiv/kg.hr, dehydrated birds 281 mu-equiv/kg.hr, while the J(Na) was half maximal at luminal Na(+) concentrations of 99 and 43 mu-equiv/l. respectively. The ;affinity' for Na(+) in the dehydrated bird was thus twice that in the normal bird. K(+) was secreted into the gut lumen at a constant rate against the electrochemical gradient, J(K) = -97 mu-equiv/kg.hr (S.E. = 5). Cl(-) was absorbed from lumen to plasma down the electrochemical gradient with J(Cl) ranging from 0 to 94 mu-equiv/kg.hr. The low J(Cl) was observed at low luminal NaCl concentrations when the J(Na) was also small.3. The solute-linked water flow, J(vs), occurring in the absence of an osmolality difference across the epithelium, was 1.1 mul. H(2)O/mu-equiv Na(+) in normal birds and 1.5 in dehydrated birds. The J(vs) was calculated as an operational parameter in experiments with luminal osmolalities different from plasma osmolality by subtracting the water flow observed in an experiment without Na(+) in the perfusion fluid from the water flow in an experiment with Na(+) containing perfusion fluids, both fluids being of the same osmolality. J(vs) was maximal at luminal osmolalities close to plasma osmolality. These observations are compatible with the hypothesis that the J(vs) is due to an osmotic flow into a confined region between the cells.4. When the perfusion rate was lowered from 5-9 ml./kg.hr to 0.8-1.0 the incoming perfusion fluid osmolality at which net water flow across the epithelium was zero went up from 100 to 180 m-osmolal higher than plasma osmolality. This observation suggests that a significant fraction of ureteral urine in the dehydrated bird may be absorbed in the coprodeum and large intestine.

Pool water temperature control

Abstract: A dual temperature control system to regulate separately the water temperature in a swimming pool and in an adjacent therapeutic pool with the use of a single heater and circulating pump. Valve means in one position direct substantially all circulating water to the swimming pool at low back pressure and in a second position direct substantially all water flow to the therapeutic pool at a higher back pressure. A spa temperature control which is responsive to the higher back pressure or is electrically actuated in concurrence with the valve means, overrides the main heater thermostatic control and regulates the temperature of water flowing to the therapeutic pool at a level higher than that normally supplied to the swimming pool.

Internal Water Status and Water Transport in Seed Onion Plants1

Abstract: Water potential, transpiration rate, and stomatal resistance of the various parts of the onion (Allium cepa L.) plant were measured under field and controlled conditions. Water potentials of florets and pedicels were always lower than leaf water potentials. Water potential difference between the florets and the soil of as much as ∗9 bars were found. The greatest drop in water potential was found between the flowers and the upper part of the seed stalk. These differences in water potential were found even when plants were growing in soil well supplied with water. Transpiration rates of the leaves were the greatest of all plant parts, the seed stalk next (about 15 to 20% of the flux density from the leaves), and the umbel lowest, representing a very small fraction of the total. Stomatal resistance of the leaves was at all times lower than seed stalk stomatal resistances. An almost on-off stomatal behavior by which the onion plant regulates its transpiration was found to operate in a narrow range of leaf water potential, ∗3 to ∗7 bars. The relation between flux density and water potential drop was found to be highly nonlinear in plants growing in different soils and under a wide range of soil water potential and environmental conditions. Impedance to water flow in the seed stalk was 5 to 8 times greater than in the leaves. For the same conditions potential drop between soil and root surface was less than 5 cm of water.

Water relations of Fusarium wilt in tomato

Abstract: The possible causes of wilting in tomato plants infected with Fusarium oxysporum f.sp. lycopersici were examined. Determinations of leaf water potential and solute potential showed that the wilting was due to water stress. The diffusive resistance of leaves to water vapor loss in infected plants was as high as or higher than the resistance in healthy plants at a given leaf water potential, and it was concluded that an alteration in transpirational behavior did not cause water stress to occur in infected plants. Measurements of water flow through excised root systems indicated that infection did not increase the resistance of roots to water flow. When water was forced through stem segments the resistance of infected segments was found to be several times the resistance of healthy segments. However, accurate estimation of xylem resistance in infected plants was impossible by this technique because the resistance of infected segments decreased markedly as water flow occurred. Apparently, a major portion of the resistance in infected xylem can be attributed to material that was removed by abnormally high rates of water flow. In general, the results confirm the hypothesis that a high xylem resistance to water flow is the sole cause of the wilting which characterizes Fusarium wilt.

Artificial kidney cleaning apparatus

Abstract: Artificial kidney treatment apparatus comprises: A. A CLEAN WATER INLET, B. INLET MEANS FOR KIDNEY TREATING LIQUID CONCENTRATE, C. MEANS TO DELIVER THE CONCENTRATE INTO A WATER STREAM BEING CIRCULATED TO AND THROUGH THE KIDNEY, WHEREBY THE KIDNEY MAY BE WASHED BY AQUEOUSLY DILUTED TREATING LIQUID, AND D. CONTROL MEANS TO CONTROL THE SEQUENTIAL DELIVERY OF WATER FLOW TO THE KIDNEY AND DILUTE TREATING LIQUID FLOW TO THE KIDNEY.

Adjustable shower head assembly with diverter valve

Abstract: A shower head assembly having an upper and lower portion, wherein the upper portion has a diverter valve mechanism slidably mounted therein, and the lower portion of the assembly is in threaded contact with the upper portion and moveable with respect thereto, thereby altering the exit apertures of the shower head assembly and adjusting water flow therefrom.

Geophysical applications of heat and mass transfer in turbulent pipe flow

Abstract: The theory of heat and mass transfer in turbulent pipe flow is applied to a semi-infinite moist-walled cylindrical pipe to determine the longitudinal distributions of both temperature and moisture content as functions of external conditions, pipe radius and wall temperature, and flow velocity. Since many cave and mine passages approximate this model, the results are directly applicable to cave microclimate studies and mine ventilation problems. The results are found to agree well with previously published microclimate observations. The theory is also applicable to water flow in free-flow karst aquifers; specifically to the study of temperature variations and of solution kinetics under turbulent flow conditions.

Vertical Recharge of Unconfined Aquifer

Abstract: Linearized, unsteady seepage solutions are obtained for some flows which result when groundwater percolates vertically downward to the water table. Solutions are given for the case when the recharge water is spread uniformly over both a two-dimensional strip of finite width and a circular region of finite radius. Finally, the mathematical solution is compared with experimental results and with a solution obtained from the Dupuit theory.

Salt and water permeability of the epithelium of the coprodeum and large intestine in the normal and dehydrated fowl (Gallus domesticus). In vivo perfusion studies.

Abstract: 1. The transmural net flow of salt and water in the coprodeum and large intestine of normal and dehydrated hens was investigated by means of an intraluminal in vivo perfusion technique. 2. The lumen was perfused with a raffinose-electrolyte solution having a low sodium concentration (Na+ = 1 m-equiv/l.). The osmolality of the solution was adjusted in the range 66-585 m-osmolal by adding raffinose. Polyethylene glycol 4000 (PEG) served as a water marker. The experiments permitted estimation of the passive transport parameters: the reflexion coefficient (σ) of the penetrating solutes (predominantly NaCl), the Na+ mobility (ωs), and the osmotic water permeability coefficient (Posm). 3. When the luminal fluid had the same osmolality as plasma the net water flow (Jv) was zero, indicating a σ of unity. The net flow of Na+ was zero, (at Jv = 0) and a transmural electric potential difference close to zero was present both in normal and in dehydrated birds. This indicates an ωs of zero. When lumen osmolality was higher than that of plasma, no `solvent drag' effect on Na+ was demonstrated in the serosa to mucosa (s—m) direction. 4. The Posm appeared to be independent of the luminal osmolality in the range of ±200 m-osmolal from plasma osmolality. In normal birds the Posms—m was 3·2 μl./kg.hr.m-osmolal, the Posmm—s 5·8 μl./kg.hr.m-osmolal. In dehydrated birds these values were 3·6 and 10·0 respectively. Thus there seems to be rectification of water flow, and it varies with the state of hydration. 5. A net K+ flow of 15-50 μ-equiv/kg.hr in the m—s direction and a net Cl- flow of 10-50 μ-equiv/kg.hr in the s—m direction were observed. No relationship was observed between the flow of these solutes and the net water flow.

Closure of "Bed Topography Effect on Flow in a Meander"

Abstract: Stabilized bed topography in a meandering channel with fixed walls and movable bed was measured at various width-depth ratios and Froude numbers. Velocity and bed-shear distributions were measured in a fixed-bed model whose configuration conformed to the stabilized topography of the movable-bed model. An approximate theoretical analysis of the bed configuration under fully developed flow conditions shows that the transverse bed slope is directly proportional to a parameter characterizing the relative importance of fluid inertia compared with the gravity acting on a particle. Good agreement has been observed between the theoretical and experimental results in the downstream half of the model channel. The effects of formation of the bed topography on the flow characteristics are considered.

Water Surface Configuration in Channel Bends

Abstract: Water surface configuration in open-channel bends depends on the geometry of the channel. Mathematical expressions for longitudinal and transverse water surface profiles are derived from the equations of motion with the aid of order of magnitude analysis. Computed surface profiles and superelevation obtained by using mathematical expressions agree well with experimental measurements of subcritical flows in trapezoidal and natural bed meandering models. The result reveals that the channel bed topography is an important factor in determining the superelevation and water surface profiles. Inadequacy of conventional approximate methods to evaluate the superelevation is also examined.

Nonflooding perimeter skimming gutter for swimming pools

Abstract: A nonflooding perimeter skimming gutter for swimming pools is provided, including a first gutter conduit for disposition about the perimeter of a swimming pool, and adapted to carry water at a level below a predetermined level of water in the swimming pool, a retaining wall on the pool-side of the first gutter conduit over the top of which wall a skimming flow of water may run from the pool into the first gutter conduit, a second gutter conduit adapted to carry water at a level below a predetermined level of water in the first gutter conduit, and a fluid flow connection between the two gutter conduits at such level and below the top of the retaining wall allowing water flow from the first gutter conduit into the second gutter conduit whenever the water level on the first gutter conduit reaches the fluid flow connection, thereby inhibiting filling of the first gutter conduit appreciably above such level.

Effect of prostaglandin e1 on osmotic water flow and sodium transport in the toad bladder

Abstract: The pros tag landins ,which are n a t u r a l l y occurr ing p ros t ano ic a c i d d e r i v a t i v e s , a r e widely d i s t r i b u t e d i n t i s s u e s and e x h i b i t a wide v a r i e t y of e f f e c t s . They imi t a t e , modify o r an tagonize t h e a c t i o n of s e v e r a l hormones which are thought t o be mediated by adenyl cyc la se and adenosine 3',5'-monophosphate(cyclic AMP). These a spec t s a r e covered comprehensively i n a series of recent reviews,and i n t h e proceedings of t h i s conference (Bergstr6m e t al, 1968; E l i a s son , 1959;von Euler & Eliasson,1967;Hortonl1969;Ramwell & Shaw,1970). Seve ra l e f f e c t s of p ros t ag land ins have been r epor t ed on t h e r e n a l handl ing of w a t e r and e l e c t r o l y t e s ( J o h n s t o n e t a l , 1967;Vander,1968) ,on osmotic water flow i n t h e i s o l a t e d c o l l e c t i n g duct(Or1off & GranthamIl967;Grantham & O r l o f f , 1968) ,and on both water flow and sodium t r a n s p o r t a c r o s s t h e toad b ladder (Or lof f e t a1,1965)and f rog sk in (Bar ry & H a l l , 1969; Fass ina e t a l , 1 9 6 9 ; Ramwell & Shaw, 1 9 7 0 ) . The s t u d i e s r epor t ed he re are p a r t of an a t t empt t o understand t h e a c t i o n s of PGEl( l la , 15( S ) -dihydroxy-9-keto-13-transp ros t ano ic a c i d ) on osmotic water flow and sodium t r a n s p o r t i n t he toad b ladder , t o i n v e s t i g a t e t h e r e l a t i o n s h i p of P G E l w i th vasopress in and t o determine t h e probable mechanism of a c t i o n of PGEl .

Flow Visualization in Turbulent Boundary Layers

Abstract: Visual observation of flow in a fully developed turbulent boundary layer along a two-dimensional channel has revealed the presence of systematic vortices both in the longitudinal and the transverse directions. In some cases a pair of longitudinal vortices has been observed connected together by a transverse one in a horseshoe configuration. As the vortices are convected downstream they grow and decay, finally dispersing as new structures are formed. An attempt has been made to characterize these vortex structures in terms of the wall layer parameters.

Soil Water Movement to Germinating Seeds

Abstract: Water movement to germinating seeds of several range plants was measured with a gamma ray attenuation technique. Seeds were placed at a depth of 1-5 cm in soil at several water contents and the soil water content of thin (3 mm) layers above and below the seeds was measured daily. It was found that the distance from which water was taken up by the seeds did not exceed 1 cm and was not affected by soil water content. Germination was found to be dependent on seed water uptake, which was determined by soil water content. The rate of seedling root growth was not affected by initial soil water content, but shoot growth was strongly affected. Solutions of the water flow equation were applied to the case of spheric geometry and infinite medium and to the case of linear flow and semi-infinite medium, in order to calculate water movement to a germinating seed or to a layer of seeds. Both the calculations and the measurements showed that water uptake by a 2-mm-diameter seed from distances exceeding 1 cm was negligible.

The role of intercellular channels in the transepithelial transfer of water and sodium in the frog urinary bladder.

Abstract: Epithelial cells of frog urinary bladders fixed in different physiological states were examined by electron microscopy. It was shown: (1) that when bladders incubated with a hypotonic mucosal medium are water-permeabilized with oxytoxin, arginine-vasotocin, cyclic 3′,5′-AMP and theophylline, this leads to a cellular swelling and the opening of intercellular channels; (2) that these effects are not observed when the transepithelial net water flow is suppressed by abolishing the external osmotic driving force; and (3) that modifications in the rate of active sodium transport do not change the morphological appearance of intercellular channels. These results are expecially discussed with respect to the localization to the intracellular site of the final effect of antidiuretic hormone on water permeability, and to the role of intercellular channels in the transepithelial transfer of water and sodium.

Mobile cleaning apparatus

Abstract: Mobile cleaning apparatus including a roller supported frame carrying a container for holding a supply of cleaning liquid, a sprayer head connected to a length of flexible tubing for spraying a cleaning liquid entrained in a stream of water, a venturi unit having a main water flow passageway and a cleaning liquid inlet, a water flow control valve connected across the passageway of the venturi unit, and a pair of pressure regulating valves connected in parallel between the outlet of the pump and the inlet of the venturi unit and water flow control valve. The pressure regulating valves have water bypassing outlets which open at two widely different pressures. A water control valve is placed in the water bypass line of the pressure regulating valve which opens at the lower pressure.

Observations of the Drainage of an Ice-Dammed Lake — Strupvatnet, Troms, Norway

Abstract: The behaviour of the ice-dammed lake, Strupvatnet, Troms County, Norway, is described. Past observations are noted and related to observations in 1959 and to other ice-dammed lakes. Mechanisms for opening and maintaining water flow during a ‘hlaup’ are discussed. It is considered that Liestol's melt widening process operates after initiation by a pressure gradient across the dam. The lake and the internal drainage system of the glacier are thus linked. There is no evidence of lifting of the ice dam at Strupbreen.