scholarly journals THE INTERNAL VELOCITY FIELD IN BREAKING WAVES

1964 ◽  
Vol 1 (9) ◽  
pp. 7 ◽  
Author(s):  
Robert L. Miller ◽  
John M. Zeigler
Keyword(s):  
Breaking Waves ◽  
Return Flow ◽  
Laboratory Studies ◽  
Velocity Data ◽  
Velocity Measurements ◽  
The Third ◽  
Horizontal Velocity Component ◽  
Shoaling Waves ◽  
Internal Velocity ◽  
Direct Photograph

As far as is known, the results presented here are the first detailed measurements of the horizontal velocity component inside breaking waves. The field study was originally undertaken in 1960 to determine the presence and strength of mid-depth return flow under shoaling waves (Miller and Zeigler, 1961, 1964). In the course of the experiment, a series of measurements was made very close to the shore. During one tidal cycle, the instruments became exposed to breakers, and continued to operate. A study of the resulting data convinced us that detailed velocity measurements could be made within the natural breaker m the field. Accordingly, a series of runs was made and velocity data collected on breakers ranging from very small to storm size. This data will be presented and discussed in detail in a later portion of this paper. A number of laboratory studies have been made on breakers. These may be placed in three categories for our purposes. The first group includes detailed discussion of observations and sequential figures illustrating the development of breakers. An example is Mason (1951). The second group of papers gives some detail on the structure of breakers and presents, either by direct photograph or sketch of, the trajectory inside the breakers. Examples are Hamada (1951) and Morison and Crooke (1953). The third group of papers presents, in addition to most of the material referred to above, a series of vector maps of the internal velocity under various types of breakers, including both sinusoidal and solitary wave generated breakers. Papers in the third category include Iversen (1951), Larras (1952), and Ippen and Kulin (1955). The latter were of most direct interest to us within the context of the present study.

scholarly journals The Accelerations of a Wave Measurement Buoy Impacted by Breaking Waves in the Surf Zone

2021 ◽  
Vol 9 (2) ◽  
pp. 214
Author(s):  
Adam C. Brown ◽  
Robert K. Paasch
Keyword(s):  
Inertial Measurement Unit ◽  
Surf Zone ◽  
Spherical Wave ◽  
Breaking Waves ◽  
Measurement Unit ◽  
High Fidelity ◽  
Wave Measurement ◽  
Near Shore ◽  
Shoaling Waves ◽  
Multiple Deployments

A spherical wave measurement buoy capable of detecting breaking waves has been designed and built. The buoy is 16 inches in diameter and houses a 9 degree of freedom inertial measurement unit (IMU). The orientation and acceleration of the buoy is continuously logged at frequencies up to 200 Hz providing a high fidelity description of the motion of the buoy as it is impacted by breaking waves. The buoy was deployed several times throughout the winter of 2013–2014. Both moored and free-drifting data were acquired in near-shore shoaling waves off the coast of Newport, OR. Almost 200 breaking waves of varying type and intensity were measured over the course of multiple deployments. The characteristic signature of spilling and plunging breakers was identified in the IMU data.

Porcellio spinicornis Say (Isopoda) demography. II. A comparison between field and laboratory data

1976 ◽  
Vol 54 (6) ◽  
pp. 825-842 ◽  
Author(s):  
Donald J. McQueen
Keyword(s):  
Field Data ◽  
Laboratory Data ◽  
Field Population ◽  
Laboratory Studies ◽  
The Third ◽  
Terrestrial Isopod ◽  
Independent Laboratory ◽  
Demographic Study ◽  
June July ◽  
Rates Of Growth

Field data from a demographic study of the terrestrial isopod Porcellio spinicornis Say were analyzed and compared with laboratory data reported by McQueen and Carnio. On the study area, which covered 482.8 m2, it was observed that reproduction began when average temperatures were > 13 °C, and that about 86% of the individuals produced one brood and about 30% produced two broods. During 1972, 25 654 offspring were produced and during 1973, 27 664 offspring resulted from reproduction, which took place during May, June, July, and August. By October of both years, these animals attained sizes ranging from 10 to 30 mg and exhibited 42 to 47% survivorship. During the next summer, females grew to between 30 and 50 mg and males to between 20 and 40 mg, and survivorship ranged from 15% in May to 2% in August. During the third summer, females attained sizes ranging from 80 to 100 mg and males from 40 to 70 mg. Survivorship during this period ranged from 1% in May to 0% in August. All rates of growth, reproduction, and survival, as well as reproductive periodicity, agreed with independent laboratory studies conducted under controlled conditions. During the 3 years studied the field population remained relatively constant and appeared to be limited by temperature conditions.

An Experimental Investigation of Desensitization in Phobic Patients

1974 ◽  
Vol 124 (581) ◽  
pp. 392-401 ◽  
Author(s):  
P. Gillan ◽  
S. J. Rachman
Keyword(s):  
Experimental Investigation ◽  
Clinical Outcome ◽  
Laboratory Studies ◽  
Comparative Efficacy ◽  
Fear Reduction ◽  
The Third

The investigation had three major aims. We attempted to repeat and extend the findings of the Gelder, Marks and Wolff (1967) study of the comparative efficacy of desensitization and psychotherapy in the treatment of phobic patients. Our second aim was to isolate the effects of various components of desensitization treatment, in the manner employed in laboratory studies of fear-reduction (e.g. Davison, 1968; Rachman, 1965; Rachman, 1968). The third aim was to collect data on the relationships between psychophysiological changes and clinical outcome.

Laboratory and field studies on the degradation of fipronil in a soil

Soil Research ◽  
2002 ◽  
Vol 40 (7) ◽  
pp. 1095 ◽  
Author(s):  
Guang-Guo Ying ◽  
Rai Kookana
Keyword(s):  
Soil Moisture ◽  
Half Life ◽  
Soil Moisture Content ◽  
Soil Surface ◽  
Field Studies ◽  
Transformation Product ◽  
Laboratory Studies ◽  
The Third ◽  
High Soil Moisture ◽  
Sulfone Derivatives

Degradation of a new insecticide/termiticide, fipronil, in a soil was studied in the laboratory and field. Three metabolites of fipronil (desulfinyl, sulfide, and sulfone derivatives) were identified from soils after treatment. Laboratory studies showed that soil moisture content had a great effect on the degradation rate of fipronil and products formed. High soil moisture contents (>50%) favored the formation of a sulfide derivative of fipronil by reduction, whereas low soil moisture (<50%) and well-aerated conditions favored the formation of fipronil sulfone by oxidation. Microorganisms in soil accelerated the degradation of fipronil to sulfide and sulfone derivatives. The third transformation product, a desulfinyl derivative, was formed by photodecomposition of fipronil in water and on the soil surface under sunlight. The desulfinyl derivative degraded rapidly in field soils with a half-life of 41–55 days compared with an average half-life of 132 days for fipronil. The half-life of the 'total toxic component' (fipronil and its metabolites) in field soil was 188 days on average.

Using Drifter Velocity Measurements to Assess and Constrain Coarse-Resolution Ocean Models

2021 ◽  
Author(s):  
Mengnan Zhao ◽  
Rui M. Ponte ◽  
Ou Wang ◽  
Rick Lumpkin
Keyword(s):  
Time Variable ◽  
Ocean Dynamics ◽  
Careful Examination ◽  
Velocity Data ◽  
Velocity Measurements ◽  
Data Errors ◽  
Coarse Resolution ◽  
Surface Circulation ◽  
Ocean Models ◽  
Data Constraints

AbstractProperly fitting ocean models to observations is crucial for improving model performance and understanding ocean dynamics. Near-surface velocity measurements from the Global Drifter Program (GDP) contain valuable information about upper ocean circulation and air-sea fluxes on various space and time scales. This study explores whether GDP measurements can be used for usefully constraining the surface circulation from coarse-resolution ocean models, using global solutions produced by the consortium for Estimating the Circulation and Climate of the Ocean (ECCO) as an example. To address this problem, a careful examination of velocity data errors is required. Comparisons between an ECCO model simulation, performed without any data constraints, and GDP and Ocean Surface Current Analyses Real-time (OSCAR) velocity data, over the period 1992–2017, reveal considerable differences in magnitude and pattern. These comparisons are used to estimate GDP data errors in the context of the time-mean and time-variable surface circulations. Both instrumental errors and errors associated with limitations in model physics and resolution (representation errors) are considered. Given the estimated model-data differences, errors and signal-to-noise ratios, our results indicate that constraining ocean state estimates to GDP can have a substantial impact on the ECCO large-scale time-mean surface circulation over extensive areas. Impact of GDP data constraints on the ECCO time-variable circulation would be weaker and mainly limited to low latitudes. Representation errors contribute substantially to degrading the data impacts.

Numerical Simulation of Breaking Waves in a Wave Group by SPH

2015 ◽  
Vol 776 ◽  
pp. 151-156
Author(s):  
Ni Nyoman Pujianiki
Keyword(s):  
Surf Zone ◽  
Breaking Waves ◽  
Return Flow ◽  
Wave Group ◽  
Regular Waves ◽  
Wave Groups ◽  
Smoothed Particle ◽  
Wave Heights ◽  
Smoothed Particle Hydrodynamic ◽  
Wave Break

Smoothed Particle Hydrodynamic (SPH) numerical model is used to investigate wave group effects at breaking and after breaking by comparing individual waves in a group with equivalent regular waves. Regular wave break almost at the same position and with the same wave height. Meanwhile in a wave group, the wave breaks in the variant positions and with variant wave heights. These phenomena cause the breaking point to be more scattered in a wave group rather than in regular waves. Return flow due to the breaking of wave groups appears more significant and is extended to the full depth in the surf zone rather than in regular waves. Swash oscillations of the wave group in the surf zone appear irregular. Meanwhile in regular waves, swash oscillations are almost constant.

AN EXPERIMENTAL INVESTIGATION OF FACTORS AFFECTING ELASTIC WAVE VELOCITIES IN POROUS MEDIA

Geophysics ◽  
1958 ◽  
Vol 23 (3) ◽  
pp. 459-493 ◽  
Author(s):  
M. R. J. Wyllie ◽  
A. R. Gregory ◽  
G. H. F. Gardner
Keyword(s):  
Experimental Investigation ◽  
Porous Media ◽  
Oil And Gas ◽  
Velocity Data ◽  
Velocity Measurements ◽  
Factors Affecting ◽  
Gas Saturation ◽  
Wave Velocities ◽  
Time Average ◽  
Made In

An experimental investigation has been made of the factors which affect the velocity of vibratory signals in porous media. It is shown from the results of experiments carried out on appropriate natural and synthetic porous systems that the time‐average formula previously suggested by Wyllie, Gregory, and L. W. Gardner is of considerable utility. This formula states that [Formula: see text] where [Formula: see text] measured, [Formula: see text] in saturating liquid, [Formula: see text] in rock solid, and ϕ=volumetric porosity fraction. The effects are examined of differential compacting pressures on the applicability of this formula to consolidated and unconsolidated rocks. It is shown that the time‐average relationship cannot be applied to determine the total volumetric porosity of carbonate rocks which are vugular and fractured. In such rocks, paradoxically, this circumstance may be advantageous because of the lithological information that may be obtained from an appropriate combination of velocity and nuclear log data. The effects of oil and gas saturation on velocity have been examined experimentally and are found to be comparatively minor. The combination of velocity data with information from electric logs in order to locate zones of oil and gas saturation is shown to be generally valuable; this is particularly so when holes are drilled with oil‐base mud. Some discussion is given of the possible effects on velocity measurements of the relative wettability of rock surfaces by various liquids. Owing to instrumental limitations, it cannot necessarily be assumed that measurements made in the laboratory are directly applicable to the interpretation of velocity data obtained under field conditions.

scholarly journals A redshift database towards the Shapley supercluster region

2020 ◽  
Vol 638 ◽  
pp. A27
Author(s):  
Hernán Quintana ◽  
Dominique Proust ◽  
Rolando Dünner ◽  
Eleazar R. Carrasco ◽  
Andreas Reisenegger
Keyword(s):  
Velocity Measurement ◽  
Average Velocity ◽  
Radial Velocities ◽  
Velocity Data ◽  
Velocity Measurements ◽  
General Terms ◽  
Future Publication

We present a database and catalogue of radial velocities of galaxies towards the region of the Shapley Supercluster (SSC) based on 18 129 measured velocities for 10 702 galaxies in the approximately 300 square degree area between 12h43m00s < RA < 14h17m00s and −23° 30′00″ > Dec >   − 38° 30′00″. The database contains velocity measurements that have been reported in the literature up until 2015. It also includes 5084 velocities, corresponding to 4617 galaxies, observed by us at Las Campanas Observatory and Cerro Tololo Inter-American Observatory, which had not been reported individually until now. Of the latter, 2585 correspond to galaxies with no other previously published velocity measurement before 2015. Every galaxy in the velocity database has been identified with a galaxy extracted from the SuperCOSMOS photometric catalogues. We also provide a combined average velocity catalogue for all 10 702 galaxies with measured velocities, adopting the SuperCOSMOS positions as a homogeneous base. A general magnitude cut-off at R2 = 18.0 mag was adopted (with exceptions only for some of the new reported velocities). In general terms, we confirm the overall structure of the SSC as reported in earlier papers. However, the more extensive velocity data show finer structures, which is to be discussed in a future publication.

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