Bathymetric detection of fluvial environments through UASs and machine learning systems

In recent decades, photogrammetric and machine learning technologies have become essential for a better understanding of environmental and anthropic issues. The present work aims to respond one of the most topical problems in environmental photogrammetry, i.e., the automatic classification of dense point clouds using the machine learning (ML) technology for the refraction correction on the fluvial water table. The applied methodology for the acquisition of multiple photogrammetric flights was made through UAV drones, also in RTK configuration, for various locations along the Orco River, sited in Piedmont (Italy) and georeferenced with GNSS—RTK topographic method. The authors considered five topographic fluvial cross-sections to set the correction methodology. The automatic classification in ML has found a valid identification of different patterns (Water, Gravel bars, Vegetation, and Ground classes), in specific hydraulic and geomatic conditions. The obtained results about the automatic classification and refraction reduction led us the definition of a new procedure, with precise conditions of validity

Modello fisico per lo studio della propagazione di onde di dam-break: realizzazione e taratura

Atti del convegn

Hull and mooring design of gyroscopic-based wave energy converter

Wave energy is one of the less exploited, yet potentially more interesting renewable energy source. In a world where the energy consumption is constantly increasing, but economic and environmental reasons drive the research of alternatives to not-renewable energy sources, it’s just a matter of time before wave energy become an economically sustainable source of renewable energy. The research effort, started in the seventies, was focused on the development of devices for the harvesting of energy from the energetically rich seas of northern Europe. The work presented in this thesis is focused on the development of ISWEC, a wave energy converter based on a gyroscopic conversion of a hull motion, designed specifically to work in the Mediterranean Sea. The device, described in detail in chapter 3, was designed in the Department of Mechanics of the Polytechnic of Turin since 2005, and I worked within the research group responsible for its development. Design of a wave energy converter requires understanding the complex interactions between the device, and its energy-harvesting system, and the waves of the sea. This can be done by the use of numerical models, but experimental validation and testing are always necessary to gain a complete knowledge of such complex phenomena. A substantial part of my work was dedicated to experimental analysis of ISWEC: chapter 4 describes the analysis conducted on the 1:8 scaled model of the device, in order to adjust and validate a numerical model able to describe the device behavior. Results obtained from the experimental campaign on the 1:8 model have been used to design the hull of the full scale prototype of the device, as described in chapter 5. Chapter 6 is dedicated to the study conducted on the mooring system for ISWEC, again performed with the aid of an extensive campaign of tests on a 1:50 scaled model of the device, and of its mooring system

Dam-break on an idealised hill side: Preliminary results of a physical model

The aim of this work is to study the propagation of dam-break waves along a hillslope by mean of a physical model (basically i.e. a 3 x 4 m2 plane set downstream of a reservoir) build up in the Hydraulic Laboratory of the Politecnico di Torino. We want to recreate the water surface, to assess the shape of the flooded area and the arrival time of the wave front. The measurement facility is a high resolution CMOS camera. We measure the water height by linking the intensity of the pixels in the acquired images to the real water depth. Preliminary quantitative results are given for the 0°downstream-slope scenario and qualitative results are presented for the case of downstream inclined plane

Dam-break on an idealised hill side: Preliminary results of a physical model

The aim of this work is to study the propagation of dam-break waves along a hillslope by mean of a physical model (basically i.e. a 3 x 4 m2 plane set downstream of a reservoir) build up in the Hydraulic Laboratory of the Politecnico di Torino. We want to recreate the water surface, to assess the shape of the flooded area and the arrival time of the wave front. The measurement facility is a high resolution CMOS camera. We measure the water height by linking the intensity of the pixels in the acquired images to the real water depth. Preliminary quantitative results are given for the 0°downstream-slope scenario and qualitative results are presented for the case of downstream inclined plane

Large Laboratory Simulator of Natural Rainfall: From Drizzle to Storms

Rainfall simulators are versatile research tools that facilitate studying rain events and the many related physical phenomena. This work describes the development and validation of an indoor, large-scale rainfall simulator comprising a rain module installed 10.4 m from ground level, a redistribution screen at an adjustable distance below the rain module, and an ultra-filtered-water recirculation system. The droplet formers installed in the rain module were selected to achieve a wide range of rain intensities. The simulator was calibrated and validated using local natural rainfall data collected with a disdrometer over 30 months. The height of the rain module allows terminal velocity to be reached at ground level. At the same time, the redistribution screen and the droplet formers guarantee the wide variability of simulated rainfall in terms of intensity and the size of the drops. As a result, we show that the rain simulator, with proper calibration of the screen’s position, can reproduce measured natural rainfall over a broad range of intensities with high spatial and temporal uniformity and kinetic energy

Experimental validation of the ISWEC wave to PTO model

Wave power represents a highly promising field in the broader area of green energy and it is currently the subject of increasing research and investments. The wave energy converter (WEC) under study in this paper is a 1:8 scaled prototype of the ISWEC, a device able to harvest sea energy exploiting the inertial effect of a gyroscope. The aim of this work is to validate the numerical simulation model of the device against the results of a wave tank test campaign carried out in INSEAN facilities in Rome.In the first part of the paper the ISWEC dynamic and hydrodynamic governing laws are outlined and implemented in a numerical model. A detailed description of the 1:8 scaled prototype characteristics is provided together with the experimental setup for the tank tests. A wide range of theoretical operating conditions are considered in order to test the system dynamics as well as its control strategy, and it is discussed how different control strategies influence the system behavior and its energy production. In the last part the experimental results are compared with the output of the numerical model, which gives a good prediction of the device behavior

Modeling and optimization of a Wave Energy Converter using ANSYS AQWA

In the framework of renewable energy, Wave Power represents a highly promising resource for the production of green energy as it is characterized by very high power density values. Moreover, Marine Energy is currently still an open field, even though the amount of research investments and patents in this field has been rising in the past 40 years. Real waves are not monochromatic and are in fact a classical example of stochastic phenomena. As such, real waves are highly complex and can be studied by means of statistical frequency domain analysis. Devices able to transform this kind of energy in a more usable form, i.e. electricity, are called WECs (Wave Energy Converters). In 2009 Politecnico di Torino started studying and designing ISWEC (Inertial Sea Wave Energy Converter) to be deployed in Pantelleria Island, one of the most powerful sites in Italy. The core of the system is a one degree of freedom gyroscope enclosed in a sealed floating hull: the spinning motion of the flywheel, combined with the motion of the floating hull, produces a gyroscopic torque that can be exploited by means of a generator called PTO (Power Take Off). The gyroscope motion unloads an inertial reaction on the hull that combined with the waves, allows power absorption. The geometry of the hull and the hydrodynamic description of the system are key factors in designing such a device. The team in Politecnico di Torino chose ANSYS AQWA to tackle the hydrodynamic subproblem. The software capability that allows for the calculation of the hydrodynamic of the floating system, was fundamental in determining the most suitable geometry of ISWEC hull. The article presents and explains the results obtained using the software for the following tasks. As a first step, a parametric analysis comparing numerous geometries was carried out with AQWA-LINE. Furthermore, it was possible to use ANSYS AQWA as the core software for dynamic simulation of the whole system, implementing the gyroscope model and the dynamic interaction between the spinning gyroscope and the floating hull by means of a DLL developed in Fortran environment