scholarly journals Field measurements, laboratory tests and empirical relations for investigating the solid-to-fluid transition of a rapid earthflow

2021 ◽  
pp. 106486
Author(s):  
M. Berti ◽  
S. Castellaro ◽  
A. Zuccarini
Keyword(s):  
Laboratory Tests ◽  
Field Measurements ◽  
Empirical Relations

Flow Fields Inside Stocked Fish Cages and the Near Environment

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Lars C. Gansel ◽  
Siri Rackebrandt ◽  
Frode Oppedal ◽  
Thomas A. McClimans
Keyword(s):  
Atlantic Salmon ◽  
Water Flow ◽  
Laboratory Tests ◽  
Numerical Models ◽  
Field Measurements ◽  
Flow Patterns ◽  
Fish Swimming ◽  
Swimming Depth ◽  
Starting Point ◽  
Fish Cages

This study explores the average flow field inside and around stocked Atlantic salmon (Salmo salar L.) fish cages. Laboratory tests and field measurements were conducted to study flow patterns around and through fish cages and the effect of fish on the water flow. Currents were measured around an empty and a stocked fish cage in a fjord to verify the results obtained from laboratory tests without fish and to study the effects of fish swimming in the cage. Fluorescein, a nontoxic, fluorescent dye, was released inside a stocked fish cage for visualization of three-dimensional flow patterns inside the cage. Atlantic salmon tend to form a torus shaped school and swim in a circular path, following the net during the daytime. Current measurements around an empty and a stocked fish cage show a strong influence of fish swimming in this circular pattern: while most of the oncoming water mass passes through the empty cage, significantly more water is pushed around the stocked fish cage. Dye experiments show that surface water inside stocked fish cages converges toward the center, where it sinks and spreads out of the cage at the depth of maximum biomass. In order to achieve a circular motion, fish must accelerate toward the center of the cage. This inward-directed force must be balanced by an outward force that pushes the water out of the cage, resulting in a low pressure area in the center of the rotational motion of the fish. Thus, water is pulled from above and below the fish swimming depth. Laboratory tests with empty cages agree well with field measurements around empty fish cages, and give a good starting point for further laboratory tests including the effect of fish-induced currents inside the cage to document the details of the flow patterns inside and adjacent to stocked fish cages. The results of such experiments can be used as benchmarks for numerical models to simulate the water flow in and around net pens, and model the oxygen supply and the spreading of wastes in the near wake of stocked fish farms.

Quantification of sewer leakage by a continuous tracer method

2011 ◽  
Vol 64 (1) ◽  
pp. 132-138 ◽  
Author(s):  
V. Prigiobbe ◽  
M. Giulianelli
Keyword(s):  
Urban Areas ◽  
Structural Damage ◽  
Laboratory Tests ◽  
Low Cost ◽  
Field Measurements ◽  
Tracer Method ◽  
Catchment Scale ◽  
Chemical Tracers ◽  
Challenging Tasks ◽  
Dry Weather Flow

Water authorities interested in the evaluation of the structural state of a sewer must quantify leakage to plan strategic intervention. However, the quantification of the exfiltration and the localisation of structural damage are challenging tasks that usually require expensive and time-consuming inspections. Herein, we report one of the first applications of the QUEST-C method to quantify the exfiltration in a continuously operating sewer by dosing two chemical tracers, sodium bromide (NaBr) and lithium chloride (LiCl). The method was applied at the catchment scale in a 14-year-old sewer in Rome, Italy. Preliminary laboratory tests, field measurements, and numerical simulations showed that reliable results require the QUEST-C method to be applied to sewers without lateral inflows, during periods of quasi-steady flow, and that the travel time of the NaBr tracer is minimised. Three sewer reaches were tested and the estimated exfiltration, as a fraction of the dry weather flow (DWF), increased from 0.128 in the agricultural area to 0.208 in the urban area. Although our estimates are at the lower end of the range given in the literature (0.01–0.56 DWF), the exfiltration was not negligible, and interventions should focus on the sewers in urban areas. This illustrates the capability of the QUEST-C method to guide strategic intervention at low cost and without an interruption of sewer operation. However, careful interpretation of the results is recommended for sewers with many lateral inflows, where leakage may be overestimated.

scholarly journals Fatigue life evaluation through field measurements and laboratory tests

2010 ◽  
Vol 2 (1) ◽  
pp. 573-582 ◽  
Author(s):  
Kiana Kashefi ◽  
A. Peyman Zandi ◽  
Mostafa Zeinoddini
Keyword(s):  
Fatigue Life ◽  
Laboratory Tests ◽  
Field Measurements ◽  
Life Evaluation ◽  
Fatigue Life Evaluation

scholarly journals Laboratory tests for the optimization of mesh size for flexible debris-flow barriers

2015 ◽  
Vol 15 (12) ◽  
pp. 2597-2604 ◽  
Author(s):  
C. Wendeler ◽  
A. Volkwein
Keyword(s):  
Grain Size ◽  
Debris Flow ◽  
Laboratory Tests ◽  
Mesh Size ◽  
Field Measurements ◽  
Maximum Diameter ◽  
Small Scale ◽  
Dimensionless Numbers ◽  
Flexible Barrier ◽  
Flexible Barriers

Abstract. Flexible barriers can be used within channelized riverbeds as an effective and efficient alternative to protect from debris flows. Their retention capability strongly depends on the size of the mesh openings and the gap between the lower barrier edge and the channel's floor. The question is now whether there is a relation between the grain size distribution of the debris material and the openings of a flexible barrier. Small-scale laboratory tests were performed to study these loading aspects of flexible debris-flow barriers for the Milibach river (Canton Berne, Switzerland). In situ debris material has been used to quantify the influence of different mesh sizes and the gap between the lower barrier edge and the riverbed compared to the d90 grain size and the flow height, where d90 is the maximum diameter of 90 % of the grains. It was possible to study the filling process and the retaining behaviour of the barriers as a function of the mesh size. A reasonable retention was reached with the net having a mesh size and a basal gap smaller than or equal to d90. These relations could be transferred to the field. A dimensional analysis reveals possible dimensionless numbers that can be used to scale the laboratory results. The findings are supported by the results of similar laboratory tests using debris material from different locations and by the available field measurements.

Undrained shear strength in stability calculation of embankments and foundations on soft clays

1980 ◽  
Vol 17 (4) ◽  
pp. 591-602 ◽  
Author(s):  
Rolf Larsson
Keyword(s):  
Shear Strength ◽  
Laboratory Tests ◽  
Undrained Shear Strength ◽  
Test Results ◽  
Stability Calculation ◽  
Soft Clays ◽  
Empirical Relations ◽  
Undrained Shear

Undrained shear strength of soft clays is usually measured by field vane tests or laboratory tests. The relevance of the test results in stability calculations of embankments and foundations is discussed. Empirical relations for undrained shear strengths obtained from Scandinavian clays are compared with reported failures.

Estimation of total settlement of embankments by field measurements

1996 ◽  
Vol 33 (5) ◽  
pp. 834-841 ◽  
Author(s):  
Elmer L Matyas ◽  
Leo Rothenburg
Keyword(s):  
Laboratory Tests ◽  
Factor Versus ◽  
Field Measurements ◽  
Coefficient Of Consolidation ◽  
Consolidation Settlement ◽  
Compressibility Coefficient ◽  
Total Settlement ◽  
Degree Of Consolidation ◽  
Secondary Compressibility ◽  
Hyperbolic Method

In the absence of compressibility data from laboratory tests, the total primary consolidation settlement of a structure founded on clay can be estimated from settlement measurements taken over a period of time. In this note, the hyperbolic and Asaoka methods are applied to a case history where an embankment fill was placed on a clay exhibiting secondary compression. It is shown that significant inaccuracies in time–settlement predictions can result if an appropriate time factor versus degree of consolidation relationship is not taken into account. Key words: primary and secondary compressibility, coefficient of consolidation, field measurements, hyperbolic method, Asaoka method.

Flow Fields Inside Stocked Fish Cages and the Near Environment

2011 ◽  
Author(s):  
Lars C. Gansel ◽  
Siri Rackebrandt ◽  
Frode Oppedal ◽  
Thomas A. McClimans
Keyword(s):  
Surface Water ◽  
Atlantic Salmon ◽  
Laboratory Tests ◽  
Numerical Models ◽  
Field Measurements ◽  
Flow Patterns ◽  
Fish Swimming ◽  
Swimming Depth ◽  
Starting Point ◽  
Fish Cages

This study explores the average flow field inside and around stocked Atlantic salmon (Salmo salar L.) fish cages. Laboratory tests and field measurements were conducted to study the effects of biofouling and especially fish behaviour on the flow patterns around and through fish cages. Currents were measured around an empty and a stocked fish cage in a fjord to verify the results obtained from laboratory tests without fish and to study the effects of fish swimming in the cage. Fluorescein, a non-toxic, fluorescent dye, was released inside a stocked fish cage for visualization of 3-dimensional flow patterns inside the cage. Atlantic salmon tend to form a torus shaped school and swim in a circular path, following the net during the daytime. Current measurements around an empty and a stocked fish cage show a strong influence of fish swimming in this circular pattern: while most of the oncoming water mass passes through the empty cage, significantly more water is pushed around the stocked fish cage. Dye experiments show that surface water inside stocked fish cages converges towards the center, where it sinks and spreads out of the cage at the depth of maximum biomass. Furthermore, the converging surface water swirled in the direction of the swimming fish. In order to achieve a circular motion, fish must accelerate towards the center of the cage. This inward-directed force must be balanced by an outward force that pushes the water out of the cage, resulting in a low pressure area in the center of the rotational motion of the fish. Thus, water is pulled from above and below the fish swimming depth. The laboratory tests with empty cages agree well with field measurements around empty fish cages, and give a good starting point for further laboratory tests including the effect of fish-induced currents inside the cage to document the details of the flow patterns inside and adjacent to stocked fish cages. The results of such experiments can be used as benchmarks for numerical models to simulate the water flow in and around net pens, and model the oxygen supply and the spreading of wastes in the near wake of stocked fish farms.

Prediction of the Operating Temperature of Thrust Bearings

1981 ◽  
Vol 103 (1) ◽  
pp. 97-106 ◽  
Author(s):  
J. H. Vohr
Keyword(s):  
Heat Balance ◽  
Laboratory Tests ◽  
Operating Temperature ◽  
Field Measurements ◽  
Operating Conditions ◽  
Thrust Bearings ◽  
Pressure Distributions ◽  
Lubricant Flow ◽  
Wide Range ◽  
Balance Analysis

An analytical method is described for predicting the operating temperature of thrust bearings of the size and speed typically found in large vertical machinery. The method involves evaluating the various mechanisms by which heat is transferred from the bearing and balancing this heat loss against the calculated heat generated by viscous shearing. This heat balance analysis is combined with a comprehensive bearing computer program which evaluates bearing pressure distributions, bearing pad deflection, lubricant flow and lubricant temperature rise within the bearing film. Predicted bearing operating temperatures show excellent agreement with laboratory tests and with field measurements over a wide range of bearing sizes and operating conditions.

scholarly journals Dune geometry estimation using apparent bedload velocity as predictor variable

2018 ◽  
Vol 40 ◽  
pp. 02054
Author(s):  
Gordon Gilja ◽  
Neven Kuspilić
Keyword(s):  
Flood Control ◽  
Flow Characteristics ◽  
Predictor Variable ◽  
Field Measurements ◽  
Stationary Flow ◽  
Flow Parameters ◽  
Empirical Relations ◽  
Geometry Estimation ◽  
Transport Flow ◽  
Field Formation

Dune formation in river systems influences sediment transport, flow characteristics, bank erosion, flood control, navigation and the protection of land and infrastructure. Research on dunes is mainly flume-based, and conclusions from such research are rarely, if at all, verified with field measurements. Dune formation and geometry in terms of height, length and steepness is most commonly correlated with averaged flow parameters as flow depth. Application of relations defined in flume conditions is limited due to stationary flow conditions and extrapolation issues for natural watercourses. It is reasonable to assume that apparent bedload velocity has significant influence on dune field formation due to nature of movement of sand particles across sandy riverbed. This research investigates applicability of apparent bedload velocity as argument in empirical relations for dune geometric characteristics.

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