Experimental investigation of propagation and run-up of rockslide- generated impulse waves in a curved mountain reservoir

2021 ◽  
Author(s):  
Linfeng Han ◽  
Pingyi Wang ◽  
Ping Mu ◽  
Qingyang Ren ◽  
Yun Liu
Author(s):  
A. El-Shafei ◽  
M. El-Hakim

This paper describes the experimental application of adaptive control to Hybrid Squeeze Film Damper (HSFD) supported rotors. The HSFD has been shown to be an adaptive damper capable of providing infinite damper configurations between short and long damper configurations. Previously, theoretical investigations of the adaptive control of HSFD concentrated on the development of the model reference adaptive control (MRAC) method, as well as development of a nonlinear reference model. Simulations of the performance of the adaptive controller during run-up and coast-down indicated the superior performance of the adaptive controller. In this paper, the adaptive controller is tested on a multi-mode rotor. A test rig is designed and developed using computer control. A simple reference model is investigated consisting of a second order system. Three forms for adaptation gain are studied. The results of the experimental investigation illustrated the performance capabilities of the adaptive controller applied to the HSFD, and moreover indicated the possibility of simple design for the adaptive controller.


2015 ◽  
Vol 9 (6) ◽  
pp. 6471-6493 ◽  
Author(s):  
M. P. Lüthi ◽  
A. Vieli

Abstract. Glacier calving can cause violent impulse waves which, upon landfall, can lead to destructive tsunami-like waves. Here we present data acquired during a calving event from Eqip Sermia, an ocean-terminating glacier in West Greenland. During an exceptionally well documented event, the collapse of 9 × 105 m3 ice from a 200 m high ice cliff caused an impulse wave of 50 m height, traveling at a speed of 25–30 m s-1. This wave was filmed from a tour boat in 800 m distance from the calving face, and simultaneously measured with a terrestrial radar interferometer and a tide gauge. Tsunami wave run-up height on the steep opposite shore in 4 km distance was 10–15 m, destroying infrastructure and eroding old vegetation. These observations indicate that such high tsunami waves are a recent phenomenon in the history of this glacier. Analysis of the data shows that only moderately bigger tsunami waves are to be expected in the future, even under rather extreme scenarios.


2000 ◽  
Vol 122 (4) ◽  
pp. 685-692 ◽  
Author(s):  
A. El-Shafei ◽  
M. El-Hakim

This paper describes the experimental application of adaptive control to Hybrid Squeeze Film Damper (HSFD) supported rotors. The HSFD has been shown to be an adaptive damper capable of providing infinite damper configurations between short and long damper configurations. Previously, theoretical investigations of the adaptive control of HSFD concentrated on the development of the model reference adaptive control (MRAC) method, as well as development of a nonlinear reference model. Simulations of the performance of the adaptive controller during run-up and coast-down indicated the superior performance of the adaptive controller. In this paper, the adaptive controller is tested on a multi-mode rotor. A test rig is designed and developed using computer control. A simple reference model is investigated consisting of a second order system. Three forms for adaptation gain are studied. The results of the experimental investigation illustrated the performance capabilities of the adaptive controller applied to the HSFD, and moreover indicated the possibility of simple design for the adaptive controller. [S0742-4795(00)01603-3]


2020 ◽  
Author(s):  
Frederic M. Evers ◽  
Robert M. Boes

<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>


2017 ◽  
Vol 17 (5) ◽  
pp. 657-670 ◽  
Author(s):  
Bolin Huang ◽  
Yueping Yin ◽  
Shichang Wang ◽  
Jianmin Tan ◽  
Guangning Liu

Abstract. A rocky granular flow is commonly formed after the failure of rocky bank slopes. An impulse wave disaster may also be initiated if the rocky granular flow rushes into a river with a high velocity. Currently, the granular mass–water body coupling study is an important trend in the field of landslide-induced impulse waves. In this paper, a full coupling numerical model for landslide-induced impulse waves is developed based on a non-coherent granular flow equation, i.e., the Mih equation. In this model, the Mih equation for continuous non-coherent granular flow controls movements of sliding mass, the two-phase flow equation regulates the interaction between sliding mass and water, and the renormalization group (RNG) turbulence model governs the movement of the water body. The proposed model is validated and applied for the 2014 Tangjiaxi landslide of the Zhexi Reservoir located in Hunan Province, China, to analyze the characteristics of both landslide motion and its following impulse waves. On 16 July 2014, a rocky debris flow was formed after the failure of the Tangjiaxi landslide, damming the Tangjiaxi stream and causing an impulse wave disaster with three dead and nine missing bodies. Based on the full coupling numerical analysis, the granular flow impacts the water with a maximum velocity of about 22.5 m s−1. Moreover, the propagation velocity of the generated waves reaches up to 12 m s−1. The maximum calculated run-up of 21.8 m is close enough to the real value of 22.7 m. The predicted landslide final deposit and wave run-up heights are in a good agreement with the field survey data. These facts verify the ability of the proposed model for simulating the real impulse wave generated by rocky granular flow events.


Author(s):  
Michael Morris-Thomas ◽  
Krish Thiagarajan ◽  
Jo̸rgen Krokstad

This paper details an experimental investigation of wave run-up on a fixed vertical surface piercing circular cylinder. The study focuses on two important parameters, wave steepness and body slenderness, which are shown to influence the wave run-up. The wave steepness, kA, is varied from 0.041–0.284, and the body slenderness parameter, ka, is varied from 0.208–1.386. The zero-, first- and second-harmonic components of the wave run-up are compared with frequency based numerical predictions of the free-surface elevation by a commercially available boundary element program, WAMIT. The comparison illustrates the importance zero- and higher-harmonic contributions to the wave run-up. In particular we show that the linear diffraction prediction of the first-harmonic component is reasonable, however, the trends exhibited by the zero- and second-harmonics are not captured well by perturbation theory. Using a regression analysis, involving a separation of ka and kA dependence, the importance of higher-order wave steepness effects on wave run-up is demonstrated.


2020 ◽  
Vol 202 ◽  
pp. 107116
Author(s):  
Wenyue Lu ◽  
Jianmin Yang ◽  
Longfei Xiao ◽  
Xiaoxian Guo ◽  
Xin Li

2011 ◽  
Vol 23 (5) ◽  
pp. 625-636 ◽  
Author(s):  
Tie-bing Shan ◽  
Jian-min Yang ◽  
Xin Li ◽  
Long-fei Xiao

1970 ◽  
Vol 1 (12) ◽  
pp. 37 ◽  
Author(s):  
Robert L. Miller

The general problem of single-impulse induced waves has been under experimental investigation by the author for several years The present paper is confined to a presentation of the wave modes which are to be expected for various permutations of displacement velocity and displacement length at the impulse source Other portions of the study will be published elsewhere It is clear that a number of geometric arrangements in the laboratory may be made to generate impulse waves, for example, sudden upthrust or downdrop of a block on the tank bottom analagous to block faulting on the sea-floor in nature, or a hinged flap moving on the bottom analagous to the undulatory bottom motion which may occur during seismic disturbances on the sea floor However, it is my opinion that the impulse generator which is most simple and most easily related to contemporary generalized theory, is a single piston thrust at one end of the wave tank which pushes the fluid down channel (See Figure 1) As an additional simplification, the investigation is carried out for the flat bottom, fixed depth case, relegating the effect of varying depth to a later study.


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