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H.-E. Minor

Bio: H.-E. Minor is an academic researcher from École Polytechnique Fédérale de Lausanne. The author has contributed to research in topics: Wave propagation & Wave shoaling. The author has an hindex of 4, co-authored 5 publications receiving 595 citations.

Papers
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Journal ArticleDOI
TL;DR: In this article, landslide generated impulse waves were investigated in a two-dimensional physical laboratory model based on the generalized Froude similarity, and four wave types were determined: weakly nonlinear oscillatory wave, nonlinear transition wave, solitary-like wave and dissipative transient bore.
Abstract: Landslide generated impulse waves were investigated in a two-dimensional physical laboratory model based on the generalized Froude similarity. The recorded wave profiles were extremely unsteady and nonlinear. Four wave types were determined: weakly nonlinear oscillatory wave, non-linear transition wave, solitary-like wave and dissipative transient bore. Most of the generated impulse waves were located in the intermediate water depth wave regime. Nevertheless the propagation velocity of the leading wave crest closely followed the theoretical approximations for a solitary wave. Between 4 and 50% of the kinetic slide impact energy propagated outward in the impulse wave train. The applicability ranges of the classical nonlinear wave theories to landslide generated impulse waves were determined. The main wave characteristics were related to the landslide parameters driving the entire wave generation process. The slide Froude number was identified as the dominant parameter. The physical model results were compared to the giant rockslide generated impulse wave which struck the shores of the Lituya Bay, Alaska, in 1958.

298 citations

Journal ArticleDOI
TL;DR: In this paper, the authors applied particle image velocimetry (PIV) to landslide impact and wave generation in an extremely unsteady three-phase flow consisting of granular matter, air, and water.
Abstract: Landslide generated impulse waves were investigated in a two-dimensional physical laboratory model based on the generalized Froude similarity. Digital particle image velocimetry (PIV) was applied to the landslide impact and wave generation. Areas of interest up to 0.8 m by 0.8 m were investigated. The challenges posed to the measurement system in an extremely unsteady three-phase flow consisting of granular matter, air, and water were considered. The complex flow phenomena in the first stage of impulse wave initiation are: high-speed granular slide impact, slide deformation and penetration into the fluid, flow separation, hydrodynamic impact crater formation, and wave generation. During this first stage the three phases are separated along sharp interfaces changing significantly within time and space. Digital masking techniques are applied to distinguish between phases thereafter allowing phase separated image processing. PIV provided instantaneous velocity vector fields in a large area of interest and gave insight into the kinematics of the wave generation process. Differential estimates such as vorticity, divergence, elongational, and shear strain were extracted from the velocity vector fields. The fundamental assumption of irrotational flow in the Laplace equation was confirmed experimentally for these non-linear waves. Applicability of PIV at large scale as well as to flows with large velocity gradients is highlighted.

169 citations

Journal ArticleDOI
TL;DR: In this article, a two-dimensional physical laboratory model based on the generalized Froude similarity was used to investigate the landslide impact and wave generation in a large area of interest and gave insight into the kinematics of the wave generation process.
Abstract: Landslide generated impulse waves were investigated in a two-dimensional physical laboratory model based on the generalized Froude similarity. Digital particle image velocimetry (PIV) was applied to the landslide impact and wave generation. Areas of interest up to 0.8 m by 0.8 m were investigated. PIV provided instantaneous velocity vector fields in a large area of interest and gave insight into the kinematics of the wave generation process. Differential estimates such as vorticity, divergence, and elongational and shear strain were extracted from the velocity vector fields. At high impact velocities flow separation occurred on the slide shoulder resulting in a hydrodynamic impact crater, whereas at low impact velocities no flow detachment was observed. The hydrodynamic impact craters may be distinguished into outward and backward collapsing impact craters. The maximum crater volume, which corresponds to the water displacement volume, exceeded the landslide volume by up to an order of magnitude. The water displacement caused by the landslide generated the first wave crest and the collapse of the air cavity followed by a run-up along the slide ramp issued the second wave crest. The extracted water displacement curves may replace the complex wave generation process in numerical models. The water displacement and displacement rate were described by multiple regressions of the following three dimensionless quantities: the slide Froude number, the relative slide volume, and the relative slide thickness. The slide Froude number was identified as the dominant parameter.

124 citations

Journal ArticleDOI
TL;DR: In this paper, the characteristics of impulse waves generated in reservoirs by the impact of variable density mass flows were assessed using two-dimensional model experimentation using particle image velocimetry (PIV) and seven successive capacitance wave gages.
Abstract: The characteristics of impulse waves generated in reservoirs by the impact of variable density mass flows were assessed using two-dimensional model experimentation. Particle image velocimetry (PIV) was applied within the wave generation area at the slide impact location and the water wave profiles were measured by seven successive capacitance wave gages. The maximum relative wave amplitude and the normalized wave amplitude of the propagating wave train were correlated with the dimensionless slide quantities and the relative propagation distance, respectively. The impact Froude number was identified as the dominant parameter for slow impacting slides, whereas the water depth and the slide thickness governed the maximum possible wave amplitude for large impact Froude numbers. Four wave types were distinguished due to three different levels of wave nonlinearity associated with variable impact Froude numbers, relative slide densities, and characteristic slide geometries: nonlinear transient bore, transition wave, oscillatory wave, and nonbreaking solitary wave. Moreover, the density effect on the wave generation process was investigated with small impact Froude numbers using sequential PIV velocity vector fields.

83 citations

Book ChapterDOI
01 Jan 2008
TL;DR: In this paper, a modern approach based on a theoretical background of debris flow research is described to assess the debris flow activity and intensity in satisfactory detail and therefore allows to derive recommendations for structural and nonstructural measures.
Abstract: strations dealt in the past and currently deal with the danger of debris flow. After a brief description of main debris flow features, the time series of debris flow events and the history of training works at the Tschengls torrent are reported. Finally, a modern approach based on a theoretical background of debris flow research is described. The integral analysis allows us to assess the debris flow activity and intensity in satisfactory detail and therefore allows us to derive recommendations for structural and nonstructural measures.

2 citations


Cited by
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01 Jan 1992
TL;DR: In this article, cross-correlation methods of interrogation of successive single-exposure frames can be used to measure the separation of pairs of particle images between successive frames, which can be optimized in terms of spatial resolution, detection rate, accuracy and reliability.
Abstract: To improve the performance of particle image velocimetry in measuring instantaneous velocity fields, direct cross-correlation of image fields can be used in place of auto-correlation methods of interrogation of double- or multiple-exposure recordings. With improved speed of photographic recording and increased resolution of video array detectors, cross-correlation methods of interrogation of successive single-exposure frames can be used to measure the separation of pairs of particle images between successive frames. By knowing the extent of image shifting used in a multiple-exposure and by a priori knowledge of the mean flow-field, the cross-correlation of different sized interrogation spots with known separation can be optimized in terms of spatial resolution, detection rate, accuracy and reliability.

1,101 citations

Journal ArticleDOI
TL;DR: In this article, landslide generated impulse waves were investigated in a two-dimensional physical laboratory model based on the generalized Froude similarity, and four wave types were determined: weakly nonlinear oscillatory wave, nonlinear transition wave, solitary-like wave and dissipative transient bore.
Abstract: Landslide generated impulse waves were investigated in a two-dimensional physical laboratory model based on the generalized Froude similarity. The recorded wave profiles were extremely unsteady and nonlinear. Four wave types were determined: weakly nonlinear oscillatory wave, non-linear transition wave, solitary-like wave and dissipative transient bore. Most of the generated impulse waves were located in the intermediate water depth wave regime. Nevertheless the propagation velocity of the leading wave crest closely followed the theoretical approximations for a solitary wave. Between 4 and 50% of the kinetic slide impact energy propagated outward in the impulse wave train. The applicability ranges of the classical nonlinear wave theories to landslide generated impulse waves were determined. The main wave characteristics were related to the landslide parameters driving the entire wave generation process. The slide Froude number was identified as the dominant parameter. The physical model results were compared to the giant rockslide generated impulse wave which struck the shores of the Lituya Bay, Alaska, in 1958.

298 citations

Journal ArticleDOI
TL;DR: In this article, a review of the available approaches available to model the individual stages, or components, of a glacial lake outburst flood (GLOF) event is introduced and discussed.

211 citations

Journal ArticleDOI
TL;DR: In this article, a smooth and streamlined rigid body slides down a plane slope, starting from different initial submergence depths, and generates surface waves, different conditions of wave nonlinearity and dispersion are generated by varying the model slide initial depth.
Abstract: Large scale, three-dimensional, laboratory experiments are performed to study tsunami generation by rigid underwater landslides. The main purpose of these experiments is to both gain insight into landslide tsunami generation processes and provide data for subsequent validation of a three-dimensional numerical model. In each experiment a smooth and streamlined rigid body slides down a plane slope, starting from different initial submergence depths, and generates surface waves. Different conditions of wave nonlinearity and dispersion are generated by varying the model slide initial submergence depth. Surface elevations are measured with capacitance gauges. Runup is measured at the tank axis using a video camera. Landslide acceleration is measured with a microaccelerometer embedded within the model slide, and its time of passage is further recorded at three locations down the slope. The repeatability of experiments is very good. Landslide kinematics is inferred from these measurements and an analytic law of motion is derived, based on which the slide added mass and drag coefficients are computed. Characteristic distance and time of slide motion, as well as a characteristic tsunami wavelength, are parameters derived from these analyses. Measured wave elevations yield characteristic tsunami amplitudes, which are found to be well predicted by empirical equations derived in earlier work, based on two-dimensional numerical computations. The strongly dispersive nature and directionality of tsunamis generated by underwater landslides is confirmed by wave measurements at gauges. Measured coastal runup is analyzed and found to correlate well with initial slide submergence depth or characteristic tsunami amplitude.

195 citations

Journal ArticleDOI
Abstract: On July 10, 1958, an earthquake Mw 8.3 along the Fairweather fault triggered a major subaerial landslide into Gilbert Inlet at the head of Lituya Bay on the southern coast of Alaska. The landslide impacted the water at high speed generating a giant tsunami and the highest wave runup in recorded history. The megatsunami runup to an elevation of 524 m caused total forest destruction and erosion down to bedrock on a spur ridge in direct prolongation of the slide axis. A cross section of Gilbert Inlet was rebuilt at 1∶675 scale in a two-dimensional physical laboratory model based on the generalized Froude similarity. A pneumatic landslide tsunami generator was used to generate a high-speed granular slide with controlled impact characteristics. State-of-the-art laser measurement techniques such as particle image velocimetry (PIV) and laser distance sensors (LDS) were applied to the decisive initial phase with landslide impact and wave generation as well as the runup on the headland. PIV provided instantaneous velocity vector fields in a large area of interest and gave insight into kinematics of wave generation and runup. The entire process of a high-speed granular landslide impact may be subdivided into two main stages: (a) Landslide impact and penetration with flow separation, cavity formation and wave generation, and (b) air cavity collapse with landslide run-out and debris detrainment causing massive phase mixing. Formation of a large air cavity — similar to an asteroid impact — in the back of the landslide is highlighted. A three-dimensional pneumatic landslide tsunami generator was designed, constructed and successfully deployed in the tsunami wave basin at OSU. The Lituya Bay landslide was reproduced in a three-dimensional physical model at 1∶400 scale. The landslide surface velocities distribution was measured with PIV. The measured tsunami amplitude and runup heights serve as benchmark for analytical and numerical models.

194 citations