A non-invasive airborne wave monitor

Nichols, Andrew; Tait, Simon; Horoshenkov, Kirill V.; Shepherd, Simon J.

doi:10.1016/j.flowmeasinst.2013.09.006

Cited by 18 publications

(12 citation statements)

References 15 publications

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“…There are currently many techniques to remotely estimate specific flow properties. These are mostly based on optical principles (Muste et al, 2008;Nichols & Rubinato, 2016), but others use acoustics (Fukami et al, 2008;Horoshenkov & Nichols, 2012;Nichols et al, 2013) or radio waves (Plant et al, 2005). Only a few of these techniques have had a practical application in the field.…”

Section: Introductionmentioning

confidence: 99%

Free-surface behaviour of shallow turbulent flows

Muraro

Dolcetti

Nichols

et al. 2021

Journal of Hydraulic Research

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Over the last two decades, interest in the free-surface behaviour of gravity-driven shallow turbulent flows has increased considerably. It is believed that observation of free-surface behaviour can provide useful information about the hydrodynamic characteristics of the flow and enable remote retrieval of these characteristics to non-invasively and rapidly monitor river flows. At the current state the literature presents scattered knowledge and also exhibits non-uniformity in the terminology used. This paper is a review of the state-of-art of this area of research and was created with two objectives: to gather the information relevant to understand the linkages between the free-surface behaviour and underpinning hydrodynamic processes while using a uniform terminology, and to analyse the gaps in our knowledge of this critical topic.

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Section: Introductionmentioning

confidence: 99%

Free-surface behaviour of shallow turbulent flows

Muraro

Dolcetti

Nichols

et al. 2021

Journal of Hydraulic Research

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“…(20) to justify the choice of a single specular point for at least the mirror angle χ 0 case. If the source and receiver have the same distance to the rough surface (i.e., z 0 = z 1 ) and the receiver is positioned on the line of specular reflection with angle χ 0 from the smooth surface S 0 (i.e., R = R 1 = R 2 ), then the gradient of the phase (20) will give the following approximate coordinates of the specular point:…”

Section: B Methods Of Stationary Phasementioning

confidence: 99%

“…The acoustical method which is able to estimate the flow Reynolds number within a 5% accuracy, provided the acoustic setup is calibrated. This technique is more simple than others such as acoustic phase tracking 20 or Doppler backscattering technique 21 which requires more sophisticated data analysis.…”

Section: The Relationship With the Hydraulic Parametersmentioning

confidence: 99%

A non-invasive acoustical method to measure the mean roughness height of the free surface of a turbulent shallow water flow

Krynkin

Horoshenkov

Nichols

et al. 2014

Review of Scientific Instruments

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In this paper, the directivity of the airborne sound field scattered by a dynamically rough free flow surface in a flume is used to determine the mean roughness height for six hydraulic conditions in which the uniform depth of the turbulent flow. The nonlinear curve fitting method is used to minimize the error between the predicted directivity and directivity data. The data fitting algorithm is based on the averaged solution for the scattered sound pressure as a function of angle which is derived through the Kirchhoff integral and its approximations. This solution takes into account the directivity of the acoustic source. For the adopted source and receiver geometry and acoustic frequency it is shown that the contribution from the stationary phase point (single specular point on the rough surface) yields similar results to those which can be obtained through the full Kirchhoff's integral. The accuracy in the inverted mean roughness height is comparable to that achieved with an array of conductive wave probes. This method enables non-invasive estimation of the flow Reynolds number and uniform flow depth.

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“…The promising future of other acoustic techniques for velocity (Razaz et al 2015, Muste et al 2016, Thomas et al 2017, Leng and Chanson 2017 and free surface determination (Nichols et al 2013, Krykin et al 2014 motivates this research which aims to assess the performance of a pulse-echo ultrasonic sensor for common environmental flows. Different common environmental flows have been studied both by means of ultrasonic sensors and a high-speed camera in the following sections.…”

Section: Introductionmentioning

confidence: 99%

On the estimation of free-surface turbulence using ultrasonic sensors

Zhang

Valero

Bung

et al. 2018

Flow Measurement and Instrumentation

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Accurate determination of free-surface dynamics has attracted much research attention during the past decade and has important applications in many environmental and water related areas. In this study, the free-surface dynamics in several turbulent flows commonly found in nature were investigated using a synchronised setup consisting of an ultrasonic sensor and a high-speed video camera. Basic sensor capabilities were examined in dry conditions to allow for a better characterisation of the present sensor model. The ultrasonic sensor was found to adequately reproduce free-surface dynamics up to the second order, especially in two-dimensional scenarios with the most energetic modes in the low frequency range. The sensor frequency response was satisfactory in the sub-20 Hz band, and its signal quality may be further improved by low-pass filtering prior to digitisation. The application of the USS to characterise entrapped air in high-velocity flows is also discussed.

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A non-invasive airborne wave monitor

Cited by 18 publications

References 15 publications

Free-surface behaviour of shallow turbulent flows

Free-surface behaviour of shallow turbulent flows

A non-invasive acoustical method to measure the mean roughness height of the free surface of a turbulent shallow water flow

On the estimation of free-surface turbulence using ultrasonic sensors

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