Journal articles: 'In-stream experiments'

1

Kuo, S. P. "Oscillating two-stream instability in ionospheric heating experiments." Physics of Plasmas 9, no. 4 (April 2002): 1456–59. http://dx.doi.org/10.1063/1.1453471.

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2

Packman, AI, and NH Brooks. "Colloidal particle exchange between stream and stream bed in a laboratory flume." Marine and Freshwater Research 46, no. 1 (1995): 233. http://dx.doi.org/10.1071/mf9950233.

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The exchange of fine natural particles between the surface and pore waters of a sand-bed stream has been investigated in a laboratory flume. At the beginning of each experiment, kaolinite clay is added to the recirculating surface water flowing over a sand bed with dunes. Transport of clay into the bed is then determined by measuring the decrease of clay concentration in the surface water with time. Two conclusions can be drawn from the experiments done to date. First, although the kaolinite particles are too small to settle appreciably in the surface flow, they can be trapped to a great extent in the bed. Second, the trapped clay can be released when the surface water no longer has a high clay concentration.

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Sánchez-Silva, F., I. Carvajal-Mariscal, M. Toledo-Velázquez, D. Libreros, M. Toledo-Velázquez, and H. Saidani-Scott. "Experiments in a combined up stream downstream slug flow." EPJ Web of Conferences 45 (2013): 01082. http://dx.doi.org/10.1051/epjconf/20134501082.

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4

Cafiero, Gioacchino, and Andrew W. Woods. "Experiments on mixing in wakes in shallow water." Journal of Fluid Mechanics 804 (September 9, 2016): 351–69. http://dx.doi.org/10.1017/jfm.2016.505.

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We report on a series of laboratory experiments in which we investigate the mixing in a wake produced downstream of an obstacle in a uniform flow. The fluid is confined within a channel of finite width, and the water depth is small compared with the channel width. The mixing appears to be dominated by dispersion caused by the circulation of the eddies that are shed alternately from each side of the obstacle. However, due to bottom friction, these eddies gradually dissipate downstream. In turn, the intensity of the cross-stream mixing of the tracer decays in the downstream direction, limiting the cross-stream extent of the tracer. We present a time-averaged picture of the experiments which illustrates the deviation of the time-averaged flow in the wake relative to the uniform flow upstream. We then develop a time-averaged model for the flow, using mixing length theory to account for the cross-channel momentum transfer as an eddy viscosity $\unicode[STIX]{x1D706}_{1}ud$, where $2ud$ is the cross-channel integral of the perturbation in the along-channel speed associated with the wake. We also include a frictional stress to account for the bottom friction. The model predicts a similar pattern of variation of the along-channel velocity in both the along- and cross-channel directions to our experimental data. By matching the cross-channel data with the model, we find that the constant $\unicode[STIX]{x1D706}_{1}$ has value 0.2. We also analyse our experimental data to develop a time-dependent picture of the mixing of a stream of dye released into the wake. Using the model for the evolution of the flow, we develop a model for the time-averaged mixing, again based on mixing length theory. The model predicts a similar spatial distribution for the tracer in both the cross-stream and along-stream directions to that seen in our experimental data. By quantitative comparison of the model with the data, we find that the best fit of the empirical eddy diffusivity, $\unicode[STIX]{x1D706}_{2}ud$, with the data occurs with $\unicode[STIX]{x1D706}_{2}=0.22$. We discuss implications of our results for modelling cross-stream mixing in shallow turbulent flow.

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GRAZIOSI, PAOLO, and GARRY L. BROWN. "Experiments on stability and transition at Mach 3." Journal of Fluid Mechanics 472 (November 30, 2002): 83–124. http://dx.doi.org/10.1017/s0022112002002094.

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The results of an experimental study of stability, receptivity and transition of the flat-plate laminar boundary layer at Mach 3 are discussed. With a relatively low free-stream disturbance level (∼0.1%), spectra, growth rates and amplitude distributions of naturally occurring boundary layer waves were measured using hot wires. Physical (mass-flux) amplitudes in the boundary layer and free stream are reported and provide stability and receptivity results against which predictions can be directly compared. Comparisons are made between measurements of growth rates of unstable high-frequency waves and theoretical predictions based on a non-parallel, mode-averaging stability theory and receptivity assumptions; good agreement is found. In contrast, it was found that linear stability theory does not account for the measured growth of low-frequency disturbances. A detailed investigation of the disturbance fields in the free stream and on the nozzle walls provides the basis for a discussion of the source and the development of the measured boundary layer waves. Attention is drawn to the close matching in streamwise wavelengths for instability waves and the free-stream acoustic disturbances. It was also found that a calibration of the hot wire in the free stream yields a double-peak boundary layer disturbance amplitude distribution, as has been found by previous investigators, which is not consistent with the predictions of linear stability theory. This double peak was found to be an experimental anomaly which resulted from assumptions that are frequently made in the free-stream calibration procedure. A single-peak amplitude distribution across the boundary layer was established only when the hot-wire voltage was calibrated against the mean boundary layer profile. Finally, the late stages of transition, at a higher Reynolds number with a higher free-stream disturbance level, were explored. Calibrated amplitude levels are provided at locations where nonlinearities are first detected and where the mean boundary layer profile is first observed to depart from the laminar similarity solution. A qualitative discussion of the character of ensuing nonlinearities is also included.

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Coat, C. A., and G. D. Lock. "Flow visualisation experiments for turbine film cooling." Aeronautical Journal 108, no. 1086 (August 2004): 403–9. http://dx.doi.org/10.1017/s000192400000021x.

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Abstract Flow visualisation experiments related to turbine film cooling have been conducted. These investigated the fluid mechanics of coolant ejection using a large-scale, flat-plate model at engine-representative Reynolds numbers in a low-speed tunnel with ambient-temperature mainstream flow. The coolant trajectories were captured using a fine nylon mesh covered with thermochromic liquid crystals, allowing measurement of gas temperature contours in planes perpendicular to the flow. Three injection geometries were assessed: cylindrical holes with stream-wise injection, cylindrical holes with cross-stream injection, and fan-shaped holes. The data demonstrated that the cylindrical holes produced discrete jets, which lifted off the surface at high coolant-to-mainstream momentum flux ratios; these jets were characterised by the kidney-shaped stream-tubes expected for injection into cross-flow. The jets injected with cross-stream momentum exhibited a more obvious kidney-shaped cross-section, which rotated with distance downstream of injection. The jets from the fan-shaped holes were attached to the surface even at high momentum flux ratios, were more diffuse, and exhibited two cores of high temperature. The trajectory visualisation data were used to interpret the adiabatic cooling effectiveness measured at the surface.

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7

Eder, A., M. Exner-Kittridge, P. Strauss, and G. Blöschl. "Re-suspension of bed sediment in a small stream – results from two flushing experiments." Hydrology and Earth System Sciences 18, no. 3 (March 17, 2014): 1043–52. http://dx.doi.org/10.5194/hess-18-1043-2014.

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Abstract. Streams draining small watersheds often exhibit multiple peaking sedigraphs associated with single peaking hydrographs. The process reasons of the multiple sediment peaks are not fully understood but they may be related to the activation of different sediment sources such as the stream bed itself, where deposited sediments from previous events may be available for resuspension. To understand resuspension of stream bed sediments at the reach scale we artificially flooded the small stream of the HOAL Petzenkirchen catchment in Austria by pumping sediment-free water into the stream. Two short floods were produced and flow, sediment and bromide concentrations were measured at three sites with high temporal resolution. Hydrologically, the two flood events were almost identical. The peak flows decreased from 57 to 7.9 L s−1 and the flow volumes decreased from 17 to 11.3 m2 along the 590 m reach of the stream. However, a considerably smaller sediment load was resuspended and transported during the second flood due to depletion of stream bed sediments. The exception was the middle section of the stream, where more sediment was transported during the second flood event which can be explained by differences between flow velocity and wave celerity and the resulting displacement of sediments within the stream. The results indicate that the first peak of the sedigraphs of natural events in this stream is indeed caused by the resuspension of stream bed sediments, accounting for up to six percent of the total sediment load depending on total flow volume.

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8

Thomas, G. F., B. Famaey, R. Ibata, F. Renaud, N. F. Martin, and P. Kroupa. "Stellar streams as gravitational experiments." Astronomy & Astrophysics 609 (January 2018): A44. http://dx.doi.org/10.1051/0004-6361/201731609.

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Kinematically cold tidal streams of globular clusters (GC) are excellent tracers of the Galactic gravitational potential at moderate Galactocentric distances, and can also be used as probes of the law of gravity on Galactic scales. Here, we compare for the first time the generation of such streams in Newtonian and Milgromian gravity (MOND). We first computed analytical results to investigate the expected shape of the GC gravitational potential in both frameworks, and we then ran N-body simulations with the Phantom of Ramses code. We find that the GCs tend to become lopsided in MOND. This is a consequence of the external field effect which breaks the strong equivalence principle. When the GC is filling its tidal radius the lopsidedness generates a strongly asymmetric tidal stream. In Newtonian dynamics, such markedly asymmetric streams can in general only be the consequence of interactions with dark matter subhalos, giant molecular clouds, or interaction with the Galactic bar. In these Newtonian cases, the asymmetry is the consequence of a very large gap in the stream, whilst in MOND it is a true asymmetry. This should thus allow us in the future to distinguish these different scenarios by making deep observations of the environment of the asymmetric stellar stream of Palomar 5. Moreover, our simulations indicate that the high internal velocity dispersion of Palomar 5 for its small stellar mass would be natural in MOND.

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9

Eder, A., M. Exner-Kittridge, P. Strauss, and G. Blöschl. "Re-suspension of bed sediment in a small stream – results from two flushing experiments." Hydrology and Earth System Sciences Discussions 10, no. 10 (October 7, 2013): 12077–104. http://dx.doi.org/10.5194/hessd-10-12077-2013.

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Abstract. Streams draining small watersheds often exhibit multiple peaking sedigraphs associated with single peaking hydrographs. The process reasons of the multiple sediment peaks are not fully understood but they may be related to the activation of different sediment sources such as the streambed itself where deposited sediments from previous events may be available for resuspension. To understand resuspension of stream bed sediments at the reach scale we artificially flooded the small stream of the HOAL Petzenkirchen catchment in Austria by pumping sediment-free water into the stream. Two short floods were produced and flow, sediment and bromide concentrations were measured at three sites with high temporal resolution. Hydrologically, the two flood events were almost identical. The peak flows decreased from 57 to 7.9 L s−1 and the flow volumes decreased from 17 to 11.3 m3 along the 590 m reach of the stream. However, a considerably smaller sediment load was resuspended and transported during the second flood due to depletion of stream bed sediments. The exception was the middle section of the stream where more sediment was transported during the second flood event which can be explained by differences between flow velocity and wave celerity and the resulting displacement of sediments within the stream. The results indicate that the first peak of the sedigraphs of natural events in this stream is indeed caused by the resuspension of streambed sediments, accounting for up to six percent of the total sediment load depending on total flow volume.

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10

van der Veen, C. J., and I. M. Whillans. "Model experiments on the evolution and stability of ice streams." Annals of Glaciology 23 (1996): 129–37. http://dx.doi.org/10.1017/s0260305500013343.

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A simple model is developed based on the notion that on active ice streams the resistance to flow is partitioned between basal drag and lateral drag. The relative roles of these sources of resistance is determined by a friction parameter that effectively describes the strength of the bed under the ice stream. Reduction in the basal strength is caused by meltwater production, taken proportional to the product of basal drag and ice speed. The width of the ice stream is governed by the balance between entrainment or erosion of ice from the slow-moving inter-stream ridges and advection from the ridges into the ice stream. Entrainment of ridge ice is parameterized as a function of the shear stress at the lateral margins, in one case proportional to the lateral shear stress and in the second case scaled to ice-stream width. In the first formulation, the model rapidly becomes unstable but, using the second formulation, a steady state is reached with lateral drag providing all or most of the resistance to flow. The results point to the great importance of achieving an understanding of entrainment. With the second model and a wide range of parameter values, there is no cyclic behavior, with rapid flow being followed by a quiescent phase.

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11

van der Veen, C. J., and I. M. Whillans. "Model experiments on the evolution and stability of ice streams." Annals of Glaciology 23 (1996): 129–37. http://dx.doi.org/10.3189/s0260305500013343.

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A simple model is developed based on the notion that on active ice streams the resistance to flow is partitioned between basal drag and lateral drag. The relative roles of these sources of resistance is determined by a friction parameter that effectively describes the strength of the bed under the ice stream. Reduction in the basal strength is caused by meltwater production, taken proportional to the product of basal drag and ice speed. The width of the ice stream is governed by the balance between entrainment or erosion of ice from the slow-moving inter-stream ridges and advection from the ridges into the ice stream. Entrainment of ridge ice is parameterized as a function of the shear stress at the lateral margins, in one case proportional to the lateral shear stress and in the second case scaled to ice-stream width. In the first formulation, the model rapidly becomes unstable but, using the second formulation, a steady state is reached with lateral drag providing all or most of the resistance to flow. The results point to the great importance of achieving an understanding of entrainment. With the second model and a wide range of parameter values, there is no cyclic behavior, with rapid flow being followed by a quiescent phase.

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12

Hunn, Julia G., Samuel J. Macaulay, and Christoph D. Matthaei. "Food Shortage Amplifies Negative Sublethal Impacts of Low-Level Exposure to the Neonicotinoid Insecticide Imidacloprid on Stream Mayfly Nymphs." Water 11, no. 10 (October 15, 2019): 2142. http://dx.doi.org/10.3390/w11102142.

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Interactions of pesticides with biotic or anthropogenic stressors affecting stream invertebrates are still poorly understood. In a three-factor laboratory experiment, we investigated effects of the neonicotinoid imidacloprid, food availability, and population density on the New Zealand mayfly Deleatidium spp. (Leptophlebiidae). Larval mayflies (10 or 20 individuals) were exposed to environmentally realistic concentrations of imidacloprid (controls, 0.97 and 2.67 μg L−1) for nine days following five days during which individuals were either starved or fed with stream algae. Imidacloprid exposure had severe lethal and sublethal effects on Deleatidium, with effects of the lower concentration occurring later in the experiment. The starvation period had delayed interactive effects, with prior starvation amplifying imidacloprid-induced increases in mayfly impairment (inability to swim or right themselves) and immobility (no signs of movement besides twitching appendages). Few studies have investigated interactions with other stressors that may worsen neonicotinoid impacts on non-target freshwater organisms, and experiments manipulating food availability or density-dependent processes are especially rare. Therefore, we encourage longer-term multiple-stressor experiments that build on our study, including mesocosm experiments involving realistic stream food webs.

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13

Mulholland, Patrick J., Robert O. Hall, Daniel J. Sobota, Walter K. Dodds, Stuart E. G. Findlay, Nancy B. Grimm, Stephen K. Hamilton, et al. "Nitrate removal in stream ecosystems measured by 15N addition experiments: Denitrification." Limnology and Oceanography 54, no. 3 (May 2009): 666–80. http://dx.doi.org/10.4319/lo.2009.54.3.0666.

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14

Hartmann, William Morris, and Douglas Johnson. "Stream Segregation and Peripheral Channeling." Music Perception 9, no. 2 (1991): 155–83. http://dx.doi.org/10.2307/40285527.

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Two interleaved melodies, with theory tones alternating as ABAB..., can be individually followed and identified if auditory stream segregation takes place. Stream segregation can occur if the tone conditions are favorable, for example, if the tones of the different melodies are in different octaves. Using an interleaved melody identification task, we have measured the extent to which 12 different tone conditions lead to stream segregation. The purpose of the experiment is to discover whether stream segregation is mediated entirely by channeling that is established in the auditory periphery or whether more complicated principles of source grouping are at work. Peripheral channels are defined as either tonotopic (frequency based) or lateral (localized left or right). The data show that peripheral channeling is of paramount importance, suggesting that a set of rather simple rules can predict whether two interleaved melodies will be perceived as segregated or not. The data reveal a secondary effect of tone duration. Otherwise, in the absence of peripheral channeling, the experiments find little or no stream segregation, even in those cases where individual tones should clearly evoke images of different sources. Additional experiments show that interleaved melody identification is made more difficult by a transposition that maximizes the number of melodic crossings, even though the transposition may place the interleaved melodies in different keys. An appendix develops an elementary mathematics of melodic crossings and contacts.

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15

Abdel-Rahman, A. A., and M. E. Eleshaky. "Diffusion characteristics of a plane jet discharged in a wavy crossflowing stream." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 218, no. 4 (April 1, 2004): 411–23. http://dx.doi.org/10.1177/095440620421800406.

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an experimental investigation has been undertaken to study the effect of a wavy crossflow on a plane jet discharged vertically downwards in a water channel. Two groups of experiments were performed: one group for a jet discharged into a uniform crossflow; the second group for a jet discharged into a wavy crossflow. Experiments were conducted for four jet-to-crossflow-velocity ratios. For each experiment, measurements using a laser Doppler anemometry system were made at six stations downstream of the exit of the jet nozzle. During the course of the experiments, the channel flow velocity was maintained fairly constant, and the wave generated in the channel was not very steep. The results revealed that the oscillatory motion associated with the waves has a significant effect on both the mean and the turbulent velocity fields. The mean velocity profiles were found to have no maximum value, compared with those of a uniform crossflow. The effect was most pronounced in the zone of flow establishment, where a region of intense fluid mixing arises, resulting in a significant shortening of the zone and a rapid development of the jet flow.

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16

Gawne, B. "Effects of feeding by Agapetus species (Trichoptera) on the density of epilithon in an Australian upland stream." Marine and Freshwater Research 46, no. 7 (1995): 991. http://dx.doi.org/10.1071/mf9950991.

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The effects of feeding by an abundant glossosomatid trichopteran on the density of epilithon on cobbles in an upland stream were evaluated by using both exclosures and flow-through in-stream channels. The in-stream channel experiment found that Agapetus kimminsi Banks had the ability to reduce significantly the density of epilithon on experimental substrata and that this effect was more pronounced on the sides of experimental substrata. The exclosure experiment found that excluding Agapetus monticolus Banks from experimental substrata within the stream had no effect on epilithon density. The different results from the two experiments appear to be due to the use of different experimental protocols and indicate that although Agapetus species are capable of affecting the density of epilithon, they may have only a limited effect within the stream. The limited effect of Agapetus species on the density of epilithon may be due to the effects of other environmental factors (e.g. current) both on the foraging activities of Agapetus species and on the density of epilithon.

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17

Clarke, W. Craig, Ruth E. Withler, and John E. Shelbourn. "Genetic Control of Juvenile Life History Pattern in Chinook Salmon (Oncorhynchus tshawytscha)." Canadian Journal of Fisheries and Aquatic Sciences 49, no. 11 (November 1, 1992): 2300–2306. http://dx.doi.org/10.1139/f92-252.

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To investigate the genetic basis for the difference in photoperiod responses between juvenile ocean-type and stream-type chinook salmon (Oncorhynchus tshawytscha), we conducted two crossing experiments and exposed the progeny to either a short- or long-day photoperiod for 10 wk from the time of first feeding. The first experiment examined the photoperiod response of pure and reciprocal crosses among red- and white-fleshed Quesnel River (stream-type) chinook salmon. The second experiment tested the photoperiod response of pure and reciprocal crosses between Quesnel River (stream-type) and Conuma River (ocean-type) chinook salmon. In both experiments, Quesnel chinook salmon fry (both red and white fleshed) sustained a high growth rate and developed a high degree of seawater adaptability only when exposed first to a short-day photoperiod for 10 wk and then to a long-day photoperiod. In contrast, the Conuma River chinook salmon grew rapidly and developed the increased seawater adaptability characteristic of smolts when reared on either photoperiod regime. Reciprocal Conuma–Quesnel hybrids displayed the ocean-type pattern of development, indicating that the photoperiod-independent phenotype is dominant and not under maternal control.

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18

Liu, X., and W. Rodi. "Experiments on transitional boundary layers with wake-induced unsteadiness." Journal of Fluid Mechanics 231 (October 1991): 229–56. http://dx.doi.org/10.1017/s0022112091003385.

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Hot-wire measurements were carried out in boundary layers developing along a flat plate over which wakes passed periodically. The wakes were generated by cylinders moving on a squirrel cage in front of the plate leading edge. The flow situation studied is an idealization of that occurring on turbomachinery blades where unsteady wakes are generated by the preceding row of blades. The influence of wake-passing frequency on the boundary-layer development and in particular on the transition processes was examined. The hot-wire signals were processed to yield ensemble-average values and the fluctuations could be separated into periodic and stochastic turbulent components. Hot-wire traces are reported as well as time variations of periodic and ensemble-averaged turbulent fluctuations and of the boundary-layer integral parameters, yielding a detailed picture of the flow development. The Reynolds number was relatively low so that in the limiting case of a boundary layer undisturbed by wakes this remained laminar over the full length of the test plate. When wakes passed over the plate, the boundary layer was found to be turbulent quite early underneath the free-stream disturbances due to the wakes, while it remained initially laminar underneath the undisturbed free-stream regions in between. The turbulent boundary-layer stripes underneath the disturbed free stream travel downstream and grow together so that the embedded laminar regions disappear and the boundary layer becomes fully turbulent. The streamwise location where this happens moves upstream with increasing wake-passing frequency, and a clear correlation could be determined in the experiments. The results are also reported in a mean Lagrangian frame by following fluid parcels underneath the disturbed and undisturbed free stream, respectively, as they travel downstream.

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Weitbrecht, Volker, Scott A. Socolofsky, and Gerhard H. Jirka. "Experiments on Mass Exchange between Groin Fields and Main Stream in Rivers." Journal of Hydraulic Engineering 134, no. 2 (February 2008): 173–83. http://dx.doi.org/10.1061/(asce)0733-9429(2008)134:2(173).

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20

El-Shaarawi, M. A. I., M. M. Kemry, and S. A. El-Bedeawi. "Experiments on Laminar Flow about a Rotating Sphere in an Air Stream." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 201, no. 6 (November 1987): 427–38. http://dx.doi.org/10.1243/pime_proc_1987_201_146_02.

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Laminar flow about a rotating sphere which is subjected to a uniform stream of air in the direction of the axis of rotation is investigated experimentally. Measurements of the velocity components within the boundary layer and the separation angle were performed at a Reynolds number, Re, of 10 000 and Ta/Re 2 of 0, 1 and 5. These measurements are compared with the numerical solutions of the same problem where either theoretical potential or actual experimental boundary conditions are imposed on the governing equations.

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21

Hall, Robert O., Jennifer L. Tank, Daniel J. Sobota, Patrick J. Mulholland, Jonathan M. O'Brien, Walter K. Dodds, Jackson R. Webster, et al. "Nitrate removal in stream ecosystems measured by 15N addition experiments: Total uptake." Limnology and Oceanography 54, no. 3 (May 2009): 653–65. http://dx.doi.org/10.4319/lo.2009.54.3.0653.

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22

Dmitriev, Alexander S., Boris Ye Kyarginsky, Andrey I. Panas, and Sergey O. Starkov. "Experiments on Direct Chaotic Communications in Microwave Band." International Journal of Bifurcation and Chaos 13, no. 06 (June 2003): 1495–507. http://dx.doi.org/10.1142/s0218127403007345.

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We discuss a concept of Direct Chaotic Communications (DCC) that is based on the following ideas: (1) chaotic oscillator generates signals directly in a specified microwave band; (2) information component is put in the chaotic signal by means of formation of an appropriate stream of chaotic radio pulses; (3) envelope detection is used. The principle of communications is confirmed experimentally in microwave band. Transmission rates up to 100 Mbps are demonstrated.

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Hildrew, Alan G., Guy Woodward, Julie H. Winterbottom, and Stuart Orton. "Strong density dependence in a predatory insect: large-scale experiments in a stream." Journal of Animal Ecology 73, no. 3 (May 2004): 448–58. http://dx.doi.org/10.1111/j.0021-8790.2004.00819.x.

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Lancaster, Jill, and Alan G. Hildrew. "Characterizing In-stream Flow Refugia." Canadian Journal of Fisheries and Aquatic Sciences 50, no. 8 (August 1, 1993): 1663–75. http://dx.doi.org/10.1139/f93-187.

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Flow in nine streams was examined in relation to refugia for invertebrates. Areas of bed maintaining low hydraulic stress throughout the discharge hydrograph could provide flow refugia for animals during spates. In one stream, near-bed shear stress and velocity were repeatedly measured in discrete patches. Three types were identified: "fast" patches maintained high hydraulic stress, "variable" patches showed the greatest change in stress, and "slow" patches maintained low stress and thus were potential refugia. Average stress increased with discharge, but potential refugia were prominent throughout and could be important for invertebrates. Abundances of refugia in eight comparison streams were characterized by changes in the frequency distribution of flow forces with discharge. Three stream types were identified that did not simply reflect channel size or morphology. Such stream-specific flow patterns could affect the structure of comunities through the differing provision of refugia. Longitudinal transport processes in these streams were investigated by solute dilution experiments and by the application of a model to measure an aggregated "dead zone". Transport (and dead zone volume) varied among streams and further reflected their refuge potential. Clearly, flow habitat features could intervene in population and community dynamics by providing refuge from spates.

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Kohler, Jack. "Determining the extent of pressurized flow beneath Storglaciären, Sweden, using results of tracer experiments and measurements of input and output discharge." Journal of Glaciology 41, no. 138 (1995): 217–31. http://dx.doi.org/10.1017/s0022143000016129.

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AbstractTwo experiments were conducted on the drainage system beneath the Lower part of the ablation zone of Storglaciären, a small valley glacier in northern Sweden. In the first experiment, over 70 tracer tests were performed in a cluster of moulins during a 1 month period, at sub-daily intervals. In the second experiment, input- and output-discharge signals were measured on the supraglacial melt stream emptying into a moulin and on the proglacial stream to which the moulin drains. The data from these two experiments are used in an idealized model of the subglacial drainage system to calculate the percentage of the system flowing as an open channel. Results from the tracer experiment suggest that the system is pressurized to within 60-340 m of the snout, while analysis of the discharge data indicates pressurized ronduits to within 0-415 m of the snout.

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Kohler, Jack. "Determining the extent of pressurized flow beneath Storglaciären, Sweden, using results of tracer experiments and measurements of input and output discharge." Journal of Glaciology 41, no. 138 (1995): 217–31. http://dx.doi.org/10.3189/s0022143000016129.

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AbstractTwo experiments were conducted on the drainage system beneath the Lower part of the ablation zone of Storglaciären, a small valley glacier in northern Sweden. In the first experiment, over 70 tracer tests were performed in a cluster of moulins during a 1 month period, at sub-daily intervals. In the second experiment, input- and output-discharge signals were measured on the supraglacial melt stream emptying into a moulin and on the proglacial stream to which the moulin drains. The data from these two experiments are used in an idealized model of the subglacial drainage system to calculate the percentage of the system flowing as an open channel. Results from the tracer experiment suggest that the system is pressurized to within 60-340 m of the snout, while analysis of the discharge data indicates pressurized ronduits to within 0-415 m of the snout.

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27

Wang, Fei, and Xi Chen Yang. "A New Modular Coaxial Feeder Nozzle in Laser Cladding." Applied Mechanics and Materials 101-102 (September 2011): 954–57. http://dx.doi.org/10.4028/www.scientific.net/amm.101-102.954.

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The powder feeder head is studied, which is one of the key to laser cladding. In view of many coaxial nozzles that are used nowadays, we have found that while cladding is doing, most of the nozzles have poor affect on powder-gathering. So as have researched on the theoretical and experiments, we designed a new coaxial nozzle, which has a great affect on powder-gathering, and can be modular disassembled. We have researched on powder stream theoretically, shot the morphology of powder stream by using high-resolution CCD camera, and analyzed the parameters of powder stream. And this new coaxial nozzle has been used in laser cladding experiments.

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Edwards, Patrick M., and Rodney Shroufe. "Three Simple Experiments to Examine the Effect of Sediment Pollution on Algae-Based Food Webs in Streams." American Biology Teacher 78, no. 1 (January 1, 2016): 57–61. http://dx.doi.org/10.1525/abt.2016.78.1.57.

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Streams and stream macroinvertebrates are ideal natural systems for ecological inquiry. We present three simple experiments that students can use to conduct field-based investigations which illustrate the importance of algae-based food webs in streams and measure the effects of sediment pollution (scour and deposition) on stream ecological processes. Over the past 5 years, we have conducted these experiments 19 times with our students. We report on the results and reliability of these experiments and make suggestions for other educators who may want to conduct them.

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Sharma, Prerana, K. Avinash, and D. N. Gupta. "Oscillating two-stream instability in strongly coupled plasma." Laser and Particle Beams 36, no. 3 (September 2018): 376–83. http://dx.doi.org/10.1017/s0263034618000368.

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AbstractOscillating two-stream instability (OTSI) of a high amplitude laser or a plasma wave is investigated in plasmas with strongly coupled ions. It is shown that in some parameter regime, the pressure of strongly coupled ions becomes negative, which leads to enhance the bunching of ion and concomitant destabilization of OTSI. Applications of these results to ion accelerator and inertial confinement fusion experiments are discussed.

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Larkin, P. A., and D. W. McKone. "An Evaluation by Field Experiments of the McLay Model of Stream Drift." Canadian Journal of Fisheries and Aquatic Sciences 42, no. 5 (May 1, 1985): 909–18. http://dx.doi.org/10.1139/f85-115.

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The model of McLay (J. Fish. Res. Board Can. 27: 359–370) for describing the drift of stream organisms was tested in a variety of field experiments in which organisms were disturbed from the substrate and/or the natural drift was blocked. In each situation, appropriate corrections may be made for the catch of drift organisms by the sampling nets. Disturbed animals drifted at a rate much less than stream velocity. The logarithm of the distance travelled was a linear function of the logarithm of mean stream velocity and conformed to the McLay model. Similarly, the model adequately described experiments in which two disturbances were done simultaneously, when drift was blocked for a 2-h period, and when there was both disturbance and blockage. A more comprehensive version of the model was only partially successful in describing the drift at various distances downstream of a blockage sustained for 4 d, probably because of upstream migration of organisms through the substrate, spatial differences in the densities of animals in the substrate, or a reduction in drift rate at lower density in the substrate.

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Pattyn, Frank. "Numerical modelling of a fast-flowing outlet glacier: experiments with different basal conditions." Annals of Glaciology 23 (1996): 237–46. http://dx.doi.org/10.1017/s0260305500013495.

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Recent observations in Shirase Drainage Basin. Enderby Land, Antarctica, show that the ice sheet is thinning at the considerable rate of 0.5–1.0 m a−1. Surface velocities in the stream area reach more than 2000 ma−1, making Shirase Glacier one of the fastest-flowing glaciers in East Antarctica. A numerical investigation of the present stress field in Shirase Glacier shows the existence of a large transition zone 200 km in length where both shearing and stretching are of equal importance, followed by a stream zone of approximately 50 km, where stretching is the major deformation process.In order to improve insight into the present transient behaviour of the ice-sheet system, a two-dimensional time-dependent flowline model has been developed, taking into account the ice-stream mechanics. Both bedrock adjustment and ice temperature are taken into account and the temperature field is fully coupled to the ice-sheet velocity field.Experiments were carried out with different basal motion conditions in order to understand their influence on the dynamic behaviour of the ice sheet and the stream area in particular. Results revealed that when basal motion becomes the dominant deformation process, (partial) disintegration of the ice sheet is counteracted by colder basal-ice temperatures due to higher advection rates. This gives rise to a cyclic behaviour in ice-sheets response and large changes in local imbalance values.

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Pattyn, Frank. "Numerical modelling of a fast-flowing outlet glacier: experiments with different basal conditions." Annals of Glaciology 23 (1996): 237–46. http://dx.doi.org/10.3189/s0260305500013495.

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Recent observations in Shirase Drainage Basin. Enderby Land, Antarctica, show that the ice sheet is thinning at the considerable rate of 0.5–1.0 m a −1. Surface velocities in the stream area reach more than 2000 ma−1, making Shirase Glacier one of the fastest-flowing glaciers in East Antarctica. A numerical investigation of the present stress field in Shirase Glacier shows the existence of a large transition zone 200 km in length where both shearing and stretching are of equal importance, followed by a stream zone of approximately 50 km, where stretching is the major deformation process.In order to improve insight into the present transient behaviour of the ice-sheet system, a two-dimensional time-dependent flowline model has been developed, taking into account the ice-stream mechanics. Both bedrock adjustment and ice temperature are taken into account and the temperature field is fully coupled to the ice-sheet velocity field.Experiments were carried out with different basal motion conditions in order to understand their influence on the dynamic behaviour of the ice sheet and the stream area in particular. Results revealed that when basal motion becomes the dominant deformation process, (partial) disintegration of the ice sheet is counteracted by colder basal-ice temperatures due to higher advection rates. This gives rise to a cyclic behaviour in ice-sheets response and large changes in local imbalance values.

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Ibrahim, Zein Al Abidin, and Patrick Gros. "TV Stream Structuring." ISRN Signal Processing 2011 (June 16, 2011): 1–17. http://dx.doi.org/10.5402/2011/975145.

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TV stream structuring consists in detecting precisely the first and the last frames of all the programs and the breaks (commercials, trailers, station identification, bumpers) of a given stream and then in annotating all these segments with metadata. Usually, breaks are broadcasted several times during a stream. Thus, the detection of these repetitions can be considered as a key tool for stream structuring. After the detection stage, a classification method is applied to separate the repetitions in programs and breaks. In their turn, breaks repetitions are then used to classify the segments which appear only once in the stream. Finally, the stream is aligned with an electronic program guide (EPG), in order to annotate the programs. Our experiments have been applied on a 22-day long TV stream, and results show the efficiency of the proposed method in TV stream structuring.

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Balamurugan, G., and Alakesh C. Mandal. "Experiments in bypass boundary layer transition under a stream with and without shear." Journal of Physics: Conference Series 822 (April 11, 2017): 012015. http://dx.doi.org/10.1088/1742-6596/822/1/012015.

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WINTERBOTTOM, JULIE, STUART ORTON, and ALAN HILDREW. "Field experiments on the mobility of benthic invertebrates in a southern English stream." Freshwater Biology 38, no. 1 (August 1997): 37–47. http://dx.doi.org/10.1046/j.1365-2427.1997.00191.x.

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Hattanji, Tsuyoshi, Mariko Ueda, Wonsuh Song, Nobuyuki Ishii, Yuichi S. Hayakawa, Yasuhiko Takaya, and Yukinori Matsukura. "Field and laboratory experiments on high dissolution rates of limestone in stream flow." Geomorphology 204 (January 2014): 485–92. http://dx.doi.org/10.1016/j.geomorph.2013.08.027.

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Hollingsworth, Deidre E., Sean P. McAuliffe, and Barbara J. Knowlton. "Temporal Allocation of Visual Attention in Adult Attention Deficit Hyperactivity Disorder." Journal of Cognitive Neuroscience 13, no. 3 (April 1, 2001): 298–305. http://dx.doi.org/10.1162/08989290151137359.

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In two experiments, we examined the ability of adults with attention deficit hyperactivity disorder (ADHD) to preocess multiple targets appearing in a rapid serial visual presentation (RSVP) stream. Using a standard attentional blink (AB) task, subjects were required to both identify a target in the RSVP stream and detect a probe appearing in one of several posttarget serial positions. In Experiment 1, ADHD adults exhibited a protracted AB compared to controls, in that their probe detection did not improve as a function of increasing probe-to-target intervals (450-720 msec). In Experiment 2, the ADHD group performed as well as controls in detectin probes appearing immediately (i.e., 90 msec) after the target. Taken together, the results demonstrate that adults with ADHD exhibit a selective deficit in rapidly shifting attention between the target and the probe, when two appear several hundred milliseconds apart. These results suggest that adults with ADHD can use automatic (reflexive) attention to detect items in close temporal proximity in the RSVP stream, but have difficulty allocating controlled attention to multiple stimuli separated by several hundred milliseconds.

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Oropeza-Vazquez, C., E. Afanador, L. Gomez, S. Wang, R. Mohan, O. Shoham, and G. Kouba. "Oil-Water Separation in a Novel Liquid-Liquid Cylindrical Cyclone (LLCC©) Compact Separator—Experiments and Modeling." Journal of Fluids Engineering 126, no. 4 (July 1, 2004): 553–64. http://dx.doi.org/10.1115/1.1777233.

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The hydrodynamics of multiphase flow in a Liquid-Liquid Cylindrical Cyclone (LLCC) compact separator have been studied experimentally and theoretically for evaluation of its performance as a free water knockout device. In the LLCC, no complete oil-water separation occurs. Rather, it performs as a free-water knockout, delivering a clean water stream in the underflow and an oil rich stream in the overflow. A total of 260 runs have been conducted, measuring the LLCC separation efficiency for water-dominated flow conditions. For all runs, an optimal split-ratio (underflow to inlet flow rate ratio) exists, where the flow rate in the water stream is maximum, with 100% watercut. The value of the optimal split-ratio depends upon the existing inlet flow pattern, and varies between 60% and 20%. For split-ratios higher than the optimal one, the watercut in the underflow stream decreases as the split-ratio increases. A novel mechanistic model has been developed for the prediction of the complex flow behavior and the separation efficiency in the LLCC. Comparisons between the experimental data and the LLCC model predictions show excellent agreement. The model is capable of predicting both the trend of the experimental data as well as the absolute measured values. The developed model can be utilized for the design and performance analysis of the LLCC.

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Nevers, Meredith B., Kasia Przybyla-Kelly, Dawn Shively, Charles C. Morris, Joshua Dickey, and Murulee N. Byappanahalli. "Influence of sediment and stream transport on detecting a source of environmental DNA." PLOS ONE 15, no. 12 (December 28, 2020): e0244086. http://dx.doi.org/10.1371/journal.pone.0244086.

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Environmental DNA (eDNA) can be used for early detection, population estimations, and assessment of potential spread of invasive species, but questions remain about factors that influence eDNA detection results. Efforts are being made to understand how physical, chemical, and biological factors—settling, resuspension, dispersion, eDNA stability/decay—influence eDNA estimations and potentially population abundance. In a series of field and controlled mesocosm experiments, we examined the detection and accumulation of eDNA in sediment and water and the transport of eDNA in a small stream in the Lake Michigan watershed, using the invasive round goby fish (Neogobius melanostomus) as a DNA source. Experiment 1: caged fish (average n = 44) were placed in a stream devoid of round goby; water was collected over 24 hours along 120-m of stream, including a simultaneous sampling event at 7 distances from DNA source; stream monitoring continued for 24 hours after fish were removed. Experiment 2: round goby were placed in laboratory tanks; water and sediment were collected over 14 days and for another 150 days post-fish removal to calculate eDNA shedding and decay rates for water and sediment. For samples from both experiments, DNA was extracted, and qPCR targeted a cytochrome oxidase I gene (COI) fragment specific to round goby. Results indicated that eDNA accumulated and decayed more slowly in sediment than water. In the stream, DNA shedding was markedly lower than calculated in the laboratory, but models indicate eDNA could potentially travel long distances (up to 50 km) under certain circumstances. Collectively, these findings show that the interactive effects of ambient conditions (e.g., eDNA stability and decay, hydrology, settling-resuspension) are important to consider when developing comprehensive models. Results of this study can help resource managers target representative sites downstream of potential invasion sites, thereby maximizing resource use.

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Fentie, B., C. W. Rose, K. J. Coughlan, and C. A. A. Ciesiolka. "The role of the geometry and frequency of rectangular rills in the relationship between sediment concentration and stream power." Soil Research 35, no. 6 (1997): 1359. http://dx.doi.org/10.1071/s97019.

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We examined, both experimentally and theoretically, whether rilling results in higher soil erosion than would have occurred without rilling. The possibility of rilling occurs when overland flow-driven erosion processes are dominant over erosion due to raindrop impact, and that is the situation assumed in this paper. Stream power (or a quantity related to stream power such as shear stress) is commonly used to describe the driving variable in flow-driven erosion. Five flume experiments were designed to investigate the relationship between stream power and sediment concentration and how this relationship is affected by the ratio of width to depth of flow (r), and the frequency or number of rills per metre width (N) of rectangular rills. This paper presents the results of these experiments and uses a physically based soil erosion theory to show that the results of the 5 flume experiments are in accord with this theory. This theory is used to investigate the effect of all possible rectangular rill geometries and frequencies on the maximum possible sediment concentration, i.e. the sediment concentration at the transport limit, by developing general relationships for the influence of r and N on sediment concentration. It is shown that increased stream power, which can be due to rilling, does not necessarily result in higher sediment concentration.

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Downs, Robert S., and Edward B. White. "Free-stream turbulence and the development of cross-flow disturbances." Journal of Fluid Mechanics 735 (October 24, 2013): 347–80. http://dx.doi.org/10.1017/jfm.2013.484.

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AbstractThe cross-flow instability that arises in swept-wing boundary layers has resisted attempts to describe the path from disturbance initiation to transition. Following concerted research efforts, surface roughness and free-stream turbulence have been identified as the leading providers of initial disturbances for cross-flow instability growth. Although a significant body of work examines the role of free-stream turbulence in the cross-flow problem, the data more relevant to the flight environment (turbulence intensities less than 0.07 %) are sparse. A series of recent experiments indicates that variations within this range may affect the initiation or growth of cross-flow instability amplitudes, hindering comparison among results obtained in different disturbance environments. To address this problem, a series of wind tunnel experiments is performed in which the free-stream turbulence intensity is varied between 0.02 % and 0.2 % of free-stream velocity,${U}_{\infty } $. Measurements of the stationary and travelling mode amplitudes are made in the boundary layer of a 1.83 m chord,$45{{}^\circ} $swept-wing model. These results are compared to those of similar experiments at higher turbulence levels to broaden the current knowledge of this portion of the cross-flow problem. It is observed that both free-stream turbulence and surface roughness contribute to the initiation of unsteady disturbances, and that free-stream turbulence affects the development of both stationary and unsteady cross-flow disturbances. For the range tested, enhanced free-stream turbulence advances the transition location except when a subcritically spaced roughness array is employed.

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Prins, N., and J. F. Juola. "Attention Switching vs Attention Sharing in Searching Dual RSVP Streams." Perception 25, no. 1_suppl (August 1996): 122. http://dx.doi.org/10.1068/v96p0304.

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Ideas about how visual attention is distributed over space include spotlight, zoom lens, and various resource allocation models. Spotlight and serial allocation models assume that attention is narrowly focused and switches from one object to another in visual search. Zoom lens and parallel allocation models, on the other hand, describe a flexible gradient within which attention can be shared among several items simultaneously. We report two experiments in which simultaneous rapid serial visual presentations (RSVPs) of two streams of digits were used, one above and one below a fixation point. In experiment 1, subjects were told to report the digit immediately following a uniquely coloured signal digit. In some trial blocks the coloured signal digit always appeared in either the top or bottom stream, and in other blocks the signal digit could occur in either stream. Stream location probabilities were varied between blocks in order to induce strategic variations in attentional allocation. In experiment 2, subjects were told to report the first two digits visible when the fixation point changed colour. Subjects were instructed to report one digit from the top stream and one from the bottom, with report order counterbalanced between blocks. The lag between the response signal and the actual digit reported was shown to vary strongly with signal location probability (experiment 1), and the lag between items reported from the top and bottom streams depended heavily on the order of report (experiment 2). The results were more consistent with an attention-switching model than with an attention-sharing model of visual attention.

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A-Izzeddin, Emily J., and Philip M. Grove. "The Relationship Between Illusory Crescents and the Stream/Bounce Effect." Multisensory Research 34, no. 4 (October 20, 2020): 423–39. http://dx.doi.org/10.1163/22134808-bja10040.

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Abstract We conducted two experiments to evaluate Meyerhoff and Scholl’s (2018, Cognition 170, 88–94) hypothesis that illusory crescents contribute to resolutions in audiovisual stream/bounce displays. In Experiment 1, we measured illusory crescent size in the launching effect as a function of speed, overlap, and sound. In Experiment 2, we tabulated stream and bounce responses to similar stimuli with the same speed, sound, and overlap conditions as Experiment 1. Our critical manipulation of target speed spanned the range of values from typical stream/bounce investigations of ∼5 degrees/s up to the target speeds employed by Meyerhoff and Scholl ∼38 degrees/s. We replicated Meyerhoff and Scholl’s findings at higher speeds, but not at slower speeds. Critically, we found that speed influenced crescent size judgements and bouncing responses in opposite directions. As target speed increased, illusory crescent size increased (Experiment 1), but the overall percentage of bounce responses decreased (Experiment 2). Additionally, we found that sound failed to enhance illusory crescent size at slower speeds but promotes bouncing responses at all speeds. The disassociation of the effects of speed and sound on illusory crescents with those effects on reported streaming/bouncing in similar displays provides compelling evidence against Meyerhoff and Scholl’s hypothesis. Therefore, we conclude that illusory crescents do not account for the pattern of responses attributed to the stream/bounce effect.

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March, James G., Jonathan P. Benstead, Catherine M. Pringle, and Mark W. Ruebel. "Linking shrimp assemblages with rates of detrital processing along an elevational gradient in a tropical stream." Canadian Journal of Fisheries and Aquatic Sciences 58, no. 3 (March 1, 2001): 470–78. http://dx.doi.org/10.1139/f00-263.

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We experimentally excluded freshwater shrimp assemblages (Atyidae, Xiphocarididae, and Palaemonidae) to examine their effects on detrital processing and benthic insect biomass at three sites along an elevational gradient in a tropical stream in Puerto Rico. We also determined which shrimp taxon was responsible for leaf decay in a subsequent laboratory experiment. At the high-elevation site, the shrimp assemblage was dominated by Atya spp. and Xiphocaris elongata, and leaf decay rates were significantly faster in the presence of shrimps than in their absence. Laboratory experiments showed that this was primarily due to direct consumption of leaves by Xiphocaris. Shrimps had no effect on leaf decay rates at mid- and low-elevation sites where there were higher proportions of Macrobrachium spp. shrimps (which prey on Xiphocaris). Laboratory experiments showed that Xiphocaris consumed significantly less leaf material and experienced significantly higher mortality in the presence of Macrobrachium. Shrimp exclusion resulted in significantly less and significantly more insect biomass at the high- and low-elevation sites, respectively; no difference was found at the mid-elevation site. Insects played a minor role in leaf decay. Results show a strong linkage between shrimp assemblages and rates of detrital decay and illustrate the importance of conducting experiments at multiple sites.

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Fitt, A. D., J. R. Ockendon, and T. V. Jones. "Aerodynamics of slot-film cooling: theory and experiment." Journal of Fluid Mechanics 160 (November 1985): 15–27. http://dx.doi.org/10.1017/s0022112085003366.

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A simple model is proposed for the two-dimensional injection of irrotational inviscid fluid from a slot into a free stream. In a certain range of values of the ratio of free-stream to injection total heads, the film thickness satisfies a nonlinear integral equation whose solution enables the mass flow in the film to be found. Some experiments are described which both agree with this theory when it is relevant and indicate its deficiencies at other values of the total head ratio.

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Müller, T., A. Virkkula, and J. A. Ogren. "Constrained two-stream algorithm for calculating aerosol light absorption coefficient from the Particle Soot Absorption Photometer." Atmospheric Measurement Techniques 7, no. 12 (December 2, 2014): 4049–70. http://dx.doi.org/10.5194/amt-7-4049-2014.

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Abstract. We present a new correction scheme for filter-based absorption photometers based on a constrained two-stream (CTS) radiative transfer model and experimental calibrations. The two-stream model was initialized using experimentally accessible optical parameters of the filter. Experimental calibrations were taken from the literature and from dedicated experiments for the present manuscript. Uncertainties in the model and calibration experiments are discussed and uncertainties for retrieval of absorption coefficients are derived. For single-scattering albedos lower than 0.8, the new CTS method and also other correction schemes suffer from the uncertainty in calibration experiments, with an uncertainty of about 20% in the absorption coefficient. For high single-scattering albedos, the CTS correction significantly reduces errors. At a single-scattering albedo of about 0.98 the error can be reduced to 30%, whereas errors using the Bond correction (Bond et al., 1999) are up to 100%. The correction scheme was tested using data from an independent experiment. The tests confirm the modeled performance of the correction scheme when comparing the CTS method to other established correction methods.

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Müller, T., A. Virkkula, and J. A. Ogren. "Constrained two-stream algorithm for calculating aerosol light absorption coefficient from the Particle Soot Absorption Photometer." Atmospheric Measurement Techniques Discussions 6, no. 6 (December 18, 2013): 11093–144. http://dx.doi.org/10.5194/amtd-6-11093-2013.

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Abstract. We present a new correction scheme for filter-based absorption photometers based on a constrained two-stream (CTS) radiative transfer model and experimental calibrations. The two-stream model was initialized using experimentally accessible optical parameters of the filter. Experimental calibrations were taken from literature and from dedicated experiments for the present manuscript. Uncertainties of the model and calibration experiments are discussed and uncertainties for retrieval of absorption coefficients are derived. For single scattering albedos lower than 0.8, the new CTS method and also other correction schemes suffer from the uncertainty of calibration experiments, with an uncertainty of about 20% in the absorption coefficient. For high single scattering albedos the CTS correction significantly reduces error. At a single scattering albedo of about 0.98 the error can be reduced to 30%, whereas errors using the Bond correction (Bond et al., 1999) are up to 100%. The correction scheme was tested using data from an independent experiment. The tests confirm the modeled performance of the correction scheme when comparing CTS to other established correction methods.

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Dogan, Eda, R. Jason Hearst, and Bharathram Ganapathisubramani. "Modelling high Reynolds number wall–turbulence interactions in laboratory experiments using large-scale free-stream turbulence." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 375, no. 2089 (March 13, 2017): 20160091. http://dx.doi.org/10.1098/rsta.2016.0091.

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A turbulent boundary layer subjected to free-stream turbulence is investigated in order to ascertain the scale interactions that dominate the near-wall region. The results are discussed in relation to a canonical high Reynolds number turbulent boundary layer because previous studies have reported considerable similarities between these two flows. Measurements were acquired simultaneously from four hot wires mounted to a rake which was traversed through the boundary layer. Particular focus is given to two main features of both canonical high Reynolds number boundary layers and boundary layers subjected to free-stream turbulence: (i) the footprint of the large scales in the logarithmic region on the near-wall small scales, specifically the modulating interaction between these scales, and (ii) the phase difference in amplitude modulation. The potential for a turbulent boundary layer subjected to free-stream turbulence to ‘simulate’ high Reynolds number wall–turbulence interactions is discussed. The results of this study have encouraging implications for future investigations of the fundamental scale interactions that take place in high Reynolds number flows as it demonstrates that these can be achieved at typical laboratory scales. This article is part of the themed issue ‘Toward the development of high-fidelity models of wall turbulence at large Reynolds number’.

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Litunovsky, V. N., V. E. Kuznetsov, B. V. Lyublin, I. B. Ovchinnikov, and V. A. Titov. "Study of shielding layer plasma parameters in experiments on intensive plasma stream-material interaction." Fusion Engineering and Design 34-35 (March 1997): 359–63. http://dx.doi.org/10.1016/s0920-3796(96)00652-7.

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Gunell, H., M. Larsson, and N. Brenning. "Experiments on anomalous electron currents to a positive probe in a magnetized plasma stream." Geophysical Research Letters 27, no. 2 (January 15, 2000): 161–64. http://dx.doi.org/10.1029/1999gl010694.

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Journal articles on the topic 'In-stream experiments'

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