Drumming the waves: conveying coastal geoscience with rhythm

Author(s):  
Cormac Byrne ◽  
Ronadh Cox

<p>It is difficult to educate the public about geoscience and to create a message that will be heard in a noisy world. Coastal geoscience in particular—despite its growing importance as sea-level rises and storminess increases—has not penetrated effectively into the public sphere. High-energy coasts attract increasing numbers of visitors, most unaware of hazards related to stochastic wave behaviour. Photo-seekers in the Instagram era are driving up accidents in extreme environments, and it’s increasingly common for people to be caught off guard and dragged into the ocean by rogue waves. Creative ways are needed to build awareness of the hazards, as well as the beauty, of high-energy coasts.</p><p>"Drumming the Waves", a musical representation of wave interactions with boulder beaches, is an NSF-funded musician-geoscientist collaboration. Informed by the shared physics of sound and water waves, the composition will showcase how mutual interference among wave sets gives rise to chaotic seas, rogue waves, and ocean swell; and how waves can be amplified unpredictably in the coastal zone. Minimalist compositional techniques are employed to overlap and superimpose multiple series of small and seemingly inconsequential rhythmic and melodic musical events, leading to composite results that are unpredictable, sometimes chaotic, and occasionally extreme.</p><p>A visceral artistic approach helps capture the ‘feeling’ of coastal waves and the impact of their interaction with boulder beaches, conveying sea states from serene calm to extreme chaos. Audio samples recorded at coastal locations in Ireland and the UK, both in air and beneath the ocean surface, are interwoven in the soundscape. We use wave sounds both in their natural audio state and in processed form. Creating new sounds by interacting field recordings of waves with electronic audio processers provides an artistic representation of the ubiquitous power and energy present in coastal environments. The temporal and erratic nature of coastal waves informs the musical structures on a macro level, exploring the contrast between the simple rhythm of tides and swell, and the irregular ephemerality of turbulent sea conditions. On a micro level, parallels between ocean and audio waves shapes are exploited to create novel musical events by shaping LFO (low frequency oscillator) and noise gates to mimic two-dimensional coastal wave models. Periodic emergence of unexpectedly large sound events mimics hazardous rogue wave generation.</p><p>We will build educational content around the music, to contextualise and explain it, and to draw attention specifically to boulder beaches, wave hazards, and the science of high-energy coasts. Simple worksheets showing wave spectra will be paired with percussion rhythms and melody that can be layered by students, either drumming and singing together, or mixing audio loops within a DAW (Digital Audio Workstation) such as GarageBand. This will permit students to build complex spectra from simple underlying wave forms. PowerPoint slides and explanatory text, pitched at the appropriate level, will be distributed to teachers for combined music/science learning. Using music to convey the science of wave interactions and wave amplification opens new doors and prospects for engaging and educating the public.</p>

2011 ◽  
Vol 11 (2) ◽  
pp. 419-429 ◽  
Author(s):  
M. H. Dao ◽  
H. Xu ◽  
E. S. Chan ◽  
P. Tkalich

Abstract. The impact of extreme/rogue waves can lead to serious damage of vessels as well as marine and coastal structures. Such extreme waves in deep water are characterized by steep wave fronts and an energetic wave crest. The process of wave breaking is highly complex and, apart from the general knowledge that impact loadings are highly impulsive, the dynamics of the breaking and impact are still poorly understood. Using an advanced numerical method, the Smoothed Particle Hydrodynamics enhanced with parallel computing is able to reproduce well the extreme waves and their breaking process. Once the waves and their breaking process are modelled successfully, the dynamics of the breaking and the characteristics of their impact on offshore structures could be studied. The computational methodology and numerical results are presented in this paper.


2011 ◽  
Vol 11 (5) ◽  
pp. 1437-1446 ◽  
Author(s):  
J. Gemmrich ◽  
C. Garrett

Abstract. Extreme surface waves occur in the tail of the probability distribution. Their occurrence rate can be displayed effectively by plotting ln(–ln P), where P is the probability of the wave or crest height exceeding a particular value, against the logarithm of that value. A Weibull distribution of the exceedance probability, as proposed in a standard model, then becomes a straight line. Earlier North Sea data from an oil platform suggest a curved plot, with a higher occurrence rate of extreme wave and crest heights than predicted by the standard model. The curvature is not accounted for by second order corrections, non-stationarity, or Benjamin-Feir instability, though all of these do lead to an increase in the exceedance probability. Simulations for deep water waves suggest that, if the waves are steep, the curvature may be explained by including up to fourth order Stokes corrections. Finally, the use of extreme value theory in fitting exceedance probabilities is shown to be inappropriate, as its application requires that not just N, but also lnN, be large, where N is the number of waves in a data block. This is unlikely to be adequately satisfied.


2020 ◽  
Author(s):  
Alexander Dosaev ◽  
Yuliya Troitskaya

<p>Many features of nonlinear water wave dynamics can be explained within the assumption that the motion of fluid is strictly potential. At the same time, numerically solving exact equations of motion for a three-dimensional potential flow with a free surface (by means of, for example, boundary integral method) is still often considered too computationally expensive, and further simplifications are made, usually implying limitations on wave steepness. A quasi-three-dimensional model, put forward by V. P. Ruban [1], represents another approach at reducing computational cost. It is, in its essence, a two-dimensional model, formulated using conformal mapping of the flow domain, augmented by three-dimensional corrections. The model assumes narrow directional distribution of the wave field and is exact for two-dimensional waves. It was successfully applied by its author to study a nonlinear stage of of Benjamin-Feir instability and rogue waves formation.</p><p>The main aim of the present work is to explore the behaviour of the quasi-three-dimensional model outside the formal limits of its applicability. From the practical point of view, it is important that the model operates robustly even in the presence of waves propagating at large angles to the main direction (although we do not attempt to accurately describe their dynamics). We investigate linear stability of Stokes waves to three-dimensional perturbations and suggest a modification to the original model to eliminate a spurious zone of instability in the vicinity of the perpendicular direction on the perturbation wavenumber plane. We show that the quasi-three-dimensional model yields a qualitatively correct description of the instability zone generated by resonant 5-wave interactions. The values of the increment are reasonably close to those obtained from the exact equations of motion [2], despite the fact that the corresponding modes of instability consist of harmonics that are relatively far from the main direction. Resonant 5-wave interactions are known to manifest themselves in the formation of the so-called “horse-shoe” or “crescent-shaped” wave patterns, and the quasi-three-dimensional model exhibits a plausible dynamics leading to formation of crescent-shaped waves.</p><p>This research was supported by RFBR (grant No. 20-05-00322).</p><p>[1] Ruban, V. P. (2010). Conformal variables in the numerical simulations of long-crested rogue waves. <em>The European Physical Journal Special Topics</em>, <em>185</em>(1), 17-33.</p><p>[2] McLean, J. W. (1982). Instabilities of finite-amplitude water waves. <em>Journal of Fluid Mechanics</em>, <em>114</em>, 315-330.</p>


1988 ◽  
Vol 197 ◽  
pp. 415-427 ◽  
Author(s):  
Bernard Le Méhauté

A theory for water waves created by the impact of small objects such as raindrops on an initially quiescent body of water is established. Capillary and dissipative viscous effects are taken into account in addition to gravity. It is shown that the prevailing waves are in a mixed capillary–gravity regime around a wavenumber km which corresponds to the minimum value of the group velocity. The waves are described as function of time and distance by the linear superposition of two transient wave components, a ‘sub-km’ (k < km) component and a ‘super-km’ (k > km) component. The super-km components prevail at a short distance from the drop, whereas only the sub-km ones remain at a larger distance. The relative time history of the wavetrain is independent of the size of the drop, and its amplitude is proportional to the drop momentum when it hits the free surface. The wave pattern is composed of a multiplicity of rings of amplitude increasing towards the drop location and is terminated by a trailing wave with an exponential decay. The number of rings increases with time and distance.


1966 ◽  
Vol 1 (10) ◽  
pp. 26 ◽  
Author(s):  
Jan M. Jordaan

The wave action due to a sudden impulse in a body of water was studied in a wave basin with beach in the laboratory. Waves were impulsively generated in the 90 ft. tank of water, 3 ft. deep, by the impact or sudden withdrawal of a paraboloidal plunger 14 ft. in diameter. The waves had a dominant height of 2 inches and period of 3 seconds, respectively, at a distance of 50 ft. from the plunger. Such waves are scale representations of those generated by sudden impulses in the ocean, such as an underwater nuclear explosion, a sudden change in the ocean bed due to earthquakes, or the impact of a land slide. The waves produced by a downward impulse, or by an underwater explosion, form a dispersive system: whose properties are not constant as in a uniform progressive wave train. Wave periodicities, celerities and wave lengths increase with time of travel and wave heights decrease with travel distance. Theory has already been developed to predict the wave properties at a given travel time and distance for given source energy, displacement and travel path depth profile (Jordaan 1965). Measurements agree fairly well with predictions.


Fluids ◽  
2019 ◽  
Vol 4 (1) ◽  
pp. 47 ◽  
Author(s):  
Alexander Dyachenko

The waves on a free surface of 2D deep water can be split into two groups: the waves moving to the right, and the waves moving to the left. A specific feature of the four-wave interactions of water waves allows to describe the evolution of the two groups as a system of two equations. The fundamental consequence of this decomposition is the conservation of the “number of waves” in each particular group. The envelope approximation for the waves in each group of counter streaming waves is obtained.


2011 ◽  
Vol 29 (11) ◽  
pp. 2089-2099 ◽  
Author(s):  
E. Marsch ◽  
S. Bourouaine

Abstract. The fast solar wind is permeated by all kinds of plasma waves which have a broad range of wavelengths and occur on many different scales. Kinetically, a plasma wave induces ion-wave interactions which can within the quasi-linear theory be described as a diffusion process. The impact this diffusion may have on the shape of the proton velocity distribution function (VDF) is studied. We first analyse theoretically some of the possible kinetic effects of the waves on the ions. Then the model predictions are compared with the detailed in-situ plasma measurements made by the Helios spacecraft on 14 April 1976 at 0.3 AU and found to comply favourably with resonant diffusion of protons in obliquely propagating magnetohydrodynamic waves. In particular, the shape at the edges of the VDFs at positive proton velocities in the wind frame can be well explained by cyclotron-resonant diffusion of the protons in oblique fast magnetoacoustic and Alfvén waves propagating away from the Sun.


Author(s):  
Xiaojing Niu ◽  
Yixiang Chen ◽  
Haojie Zhou

A moving atmospheric pressure disturbance can induce a system of forced water waves. As predicted by the linear theory, an infinite wave height will be induced when the Froude number Fr=1, which is known as the Proudman resonance. Fr is defined as the ratio between the moving speed of an atmospheric pressure disturbance and the phase velocity of shallow water wave. The Proudman resonance is thought to be one of main mechanisms for the destructive meteotsunami (Monserrat et al., 2006). In this study, the nonlinear shallow water equations are used to describe the waves induced by a moving pressure disturbance, and the impact factors to the maximum water elevation in the case of Fr=1 are discussed.


2019 ◽  
pp. 109-123
Author(s):  
I. E. Limonov ◽  
M. V. Nesena

The purpose of this study is to evaluate the impact of public investment programs on the socio-economic development of territories. As a case, the federal target programs for the development of regions and investment programs of the financial development institution — Vnesheconombank, designed to solve the problems of regional development are considered. The impact of the public interventions were evaluated by the “difference in differences” method using Bayesian modeling. The results of the evaluation suggest the positive impact of federal target programs on the total factor productivity of regions and on innovation; and that regional investment programs of Vnesheconombank are improving the export activity. All of the investments considered are likely to have contributed to the reduction of unemployment, but their implementation has been accompanied by an increase in social inequality.


Author(s):  
EVA MOEHLECKE DE BASEGGIO ◽  
OLIVIA SCHNEIDER ◽  
TIBOR SZVIRCSEV TRESCH

The Swiss Armed Forces (SAF), as part of a democratic system, depends on legitimacy. Democracy, legitimacy and the public are closely connected. In the public sphere the SAF need to be visible; it is where they are controlled and legitimated by the citizens, as part of a deliberative discussion in which political decisions are communicatively negotiated. Considering this, the meaning of political communication, including the SAF’s communication, becomes obvious as it forms the most important basis for political legitimation processes. Social media provide a new way for the SAF to communicate and interact directly with the population. The SAF’s social media communication potentially brings it closer to the people and engages them in a dialogue. The SAF can become more transparent and social media communication may increase its reputation and legitimacy. To measure the effects of social media communication, a survey of the Swiss internet population was conducted. Based on this data, a structural equation model was defined, the effects of which substantiate the assumption that the SAF benefits from being on social media in terms of broadening its reach and increasing legitimacy values.


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