‪Impulse wave generation: a comparison of landslides of block and granular masses by coupled Lagrangian tracking using VOF over a set mesh

This paper presents the numerical results of impulsive waves generated by landslides of solid block, granular materials and heavy block sinking. An impulse product parameter P is developed and a wide range of effective parameters are studied. The volume-of-fluid (VOF) and overset mesh methods have been used to study landslide-generated tsunamis. Also, a Lagrangian tracking approach coupled with the VOF to simulate the granular movement. The effect of the water reservoir depth, the landslide height, the landslide density and the geometrical parameters on the wave height (elevation) has been investigated using the open-source OpenFOAM software. The results have been presented for dimensionless distances and the normalized geometry of the landslide in the range 5–7, 1–2, respectively. These numbers have been normalized the height of the landslide (a). According to the results of simulations, the tsunami formation process is divided into three stages, which were analyzed in detail by considering the interactions between the solid and the water reservoir. The Scott Russell wave has the highest impulse product parameter among the impulse wave mechanisms which is 58.6% of the total impulse production. In addition, the duration of the wave propagation has been computed based on the wave height.

The Compatibility between Fibonacci Sequence and Elliott Impulse Wave in the Context of A-share Market

The connections between Fibonacci sequence and Elliott impulse wave that Ralph Elliot has proposed in Elliott Wave Principle are not valid all the time owing to the type and variability of the stock market. It is a probabilistic event which can reflect the compatibility between Fibonacci sequence and Elliott impulse wave. In order to explore the compatibility between Fibonacci sequence and basic-form Elliott impulse wave in the context of Chinese A-share market, a research via analyzing the historical trend of 50 core assets’ individual stocks was conducted in Chinese A-share market. The study reveals that Fibonacci sequence does not highly fit basic-form Elliott impulse wave in the context of Chinese A-share market. Suggestions for investors are diversifying the investment strategy to enhance risk controllability, rather than using Elliott Wave Principle singly.

Complementarity Relationships and Critical Configurations in Rigid-Body Collisions of Planar Kinematic Chains With Smooth External Contacts

In this article, we consider a special class of collision problems that are frequently encountered in the field of robotics. Such problems can be described as a kinematic chain with one of its ends striking an external surface, while the remaining ends resting on other surfaces. This type of problem involves complementarity relationships between the normal velocities and impulses at the contacting ends. We present a solution method that takes into account the complementarity conditions at the contacting ends. In addition, we study the critical configurations of particle and rigid-body chains where the impulse wave generated by impact gets blocked before it reaches a contacting end.

The Propagation of Landslide-Generated Impulse Waves and Their Impacts on the Moored Ships: An Experimental Investigation

The effective prevention and reduction of the hazardous impact of landslide-generated impulse waves on the moored ships are crucial for the sustainable operation of the reservoirs. Although the investigations of landslide-generated impulse waves have been widely studied in the past decades, few efforts involved their impacts on the moored ships. The authors in this paper specifically examine the hazardous impact of the impulse waves on the moored ships by applying the physical experiments. Considering that the impulse wave was an external force acting on the mooring line, the impulse wave generation, propagation, and its impact on the moored ships are hence explored in detail. The results indicate that the impact of impulse waves on the moored ships was mainly due to the first wave amplitude and height, and an exponential function relationship between the relative wave height and wave crest amplitude was revealed. Furthermore, the attenuation of the maximum wave crest amplitude was approximated by a power exponential function. On this basis, the mooring tension could be calculated based on the linear relationship between the mooring tension and wave height. Ultimately, the safety of the moored ships in the port can be evaluated.

Ad-hoc estimation of landslide-generated impulse waves – from the lab to the field

<p>Landslide tsunamis generated by extremely rapid subaerial mass wasting are also referred to as impulse waves and may occur both along coastal areas and in inland waters including engineered reservoirs. The hydraulic process chain comprising wave generation, propagation, and run-up needs to be comprehensively assessed to predict whether these waves represent a threat to the shore and adjacent infrastructure. Hazard assessment studies based on site-specific hydraulic laboratory models and numerical simulations may generally yield quite accurate predictions of the expected wave and run-up heights. While the former involves the availability of specialized lab infrastructure and instrumentation, the latter requires in-depth knowledge of suitable numerical methods as well as experience in their application to scenarios at prototype-scale. Therefore, both approaches are time-consuming, involve high costs, and pose substantial entry thresholds for practitioners. Especially in emergency situations, when first-order estimations need to be quickly at hand, the ad-hoc applicability of these approaches may therefore be limited.</p><p>Motivated by an imminent landslide hazard at Carmena reservoir, Switzerland, in 2002, the national supervisory authority for dam safety, the Swiss Federal Office of Energy, commissioned the development of a fast and readily applicable computational procedure. As a result, the first edition of the so-called ‘impulse wave manual’ was published in 2009 and provides an extensive literature review of generally applicable equations derived from lab experiments. It combines selected equations into a coherent computational framework covering all stages of an impulse wave event’s hydraulic process chain. Based on the estimation of e.g. wave and run-up heights, this manual allows to rapidly implement mitigation measures including reservoir drawdown or precautionary evacuation. In addition to an improved emergency planning, the manual proved to be an inexpensive tool to obtain an estimation of an impulse wave event’s magnitude during the preliminary design phase of new reservoirs. Back in 2009, the manual’s literature analysis already identified specific research gaps, leading to the initiation of further experimental investigations. Following these research efforts over the past ten years, a second edition of the manual was published in 2019 featuring an updated computational procedure.</p><p>This contribution provides a brief introduction to the updated computational procedure and applies it to prototype events with available survey data, e.g. Chehalis Lake, Canada, in 2007. The comparison to prototype data allows to highlight the procedure’s capabilities as well as its limitations for future ad-hoc estimations of landslide-generated impulse waves.</p>