Ioannis Sibetheros

University of West Attica | TEIATH · Department of Civil Engineering

The present work deals with the reconstruction of the flood wave that hit Mandra town (Athens, Greece) on 15 November 2017, using the framework of forensic hydrology. The flash flood event was caused by a huge storm event with a high level of spatial and temporal variability, which was part of the Medicane Numa-Zenon. The reconstruction included: (...

Herein, a reconstruction of the flash flood of Mandra (Greece, 2017) is presented, based on field data collection and the use of two different numerical models. Specifically, we developed a field dataset of post-flood mud footprints on buildings and used it to calibrate the hydrodynamic HEC-RAS software; then, the hydrodynamic MIKE FLOOD software w...

This study deals with the 2D flood simulation of an urban flash flood event that took place on November 15, 2017 in Mandra, Attica. The well-known hydrodynamic software HEC-RAS was used for the flood simulation. The model input was an ensemble of 100 hydrographs, derived from the simulation of the rainfall-runoff process of the Agia Aikaterini catc...

Acheloos is the second longest and the largest, in terms of discharge, native river in Greece, supplying three hydroelectric dams along its route. The Kremasta dam, which forms the largest artificial lake in Greece, is the first dam fed by Acheloos and two other rivers. Sediment accumulation in such large reservoirs is of major concern, as it reduc...

Mediterranean semi-arid watersheds are characterized by a climate type with long periods of drought and infrequent but high-intensity rainfalls. These factors lead to the formation of temporary flow tributaries which present flashy hydrographs with response times ranging from minutes to hours and high erosion rates with significant sediment transpo...

River flooding causes significant losses to crops and negatively affects local agriculture economies, particularly in rural riverine areas. In this work, a techno-economic methodology for the monetary estimation of crop losses due to flash flooding is presented. The methodology takes into account flood depth and flow velocity, as provided by MIKE F...

The Mediterranean region is characterized by a unique micro-climate and a complex geologic and geomorphologic environment caused by its position in the Alpine orogenesis belt. Unique features of the region are the temporary rivers that are dry streams or streams with very low flow for most of the time over decadal time scales. One of their key char...

This paper focuses on Fluid Motion-Field Estimation from video data, which is a useful but challenging problem in environmental monitoring. Rivers are often monitored by flashy hydrographs that exhibit characteristic response times ranging from minutes to hours. In order to estimate the river discharge during a flush flood event, the temporary moti...

An image-based framework for river flow monitoring based on a statistical estimation technique for fluid flow estimation is presented. This approach uses subsequent gray-scale video frames along with a statistical estimation method to extract the optical flow. An average velocity estimate is computed using the velocity vectors of the main motion tr...

Damage curves are the most significant component of the flood loss estimation models. Their development is quite complex. Two types of damage curves exist, historical and synthetic curves. Historical curves are developed from historical loss data from actual flood events. However, due to the scarcity of historical data, synthetic damage curves can be...

In this paper, a study of the sediment transport in a complex Mediterranean watershed (i.e. the Koiliaris River Basin of Crete) consisting of temporary flow tributaries and karstic springs is presented. Both daily flow data (2005-2013) and monthly sediment concentration data (2011-2013) were used to calibrate the modified Soil and Water Assessment...

Advanced parametric processes enable the exploration of a wide range of design intentions and the generation of alternative project configurations. A novel parametric approach that integrates climatic and site data into a dynamic model of a large building project, to support architectural decisions in early design stages, is presented. Bioclimatic...

The development of a definitive predictive model that accurately accounts for the nonlinear hydrodynamics and structural response behavior observed in arrays of closely spaced risers on deep water structures will require a more detailed understanding of this fluid–structure interaction. Through the analysis and interpretation of data from model bas...

Wave run-up on deepwater offshore structures may contribute to wave overtopping of the platform deck. It may also cause undesirable loads including impact loads on the underside of the deck when combined with other hydrodynamic phenomena beneath the platform deck. In this study a 1:40 scale model of an unmanned mini-TLP design was subjected to a se...

This paper reports on some of the results of an experimental test program on the dynamic response and interactive behavior of marine risers and tendons, which was conducted in the deep water basin at the Offshore Technology Research Center (OTRC), Texas A&M University. Specifically, the paper focuses on the nonlinear system analysis of the interact...

The response of a long flexible cylinder excited by random waves in a large model basin was investigated. The linear and non-linear physical mechanisms associated with the wave–cylinder interaction were analysed using system identification and modelling techniques. A third-order frequency domain Volterra model and its orthogonalized counterpart wer...

A numerical study of the nonlinear and random behavior of flow-induced forces on offshore structures and experimental verification of the results are presented. The numerical study is based on a finite-element method for the unsteady incompressible Navier-Stokes equations in two dimensions. The momentum equations combined with a pressure correction...

The reversing nearfield flow around a cylinder in planar harmonic farfield flow at Keulegan Carpenter (KC) numbers in the drag-inertia dominated flow regime and at subcritical Reynolds numbers was investigated. The objective was to measure, map, and analyze the instantaneous flow field around the cylinder, and to improve our understanding of the re...

The method of characteristics (MOC) with spline polynomials for interpolations was investigated for numerical water hammer analysis for a frictionless horizontal pipe. A new analysis quantifies numerical errors in a systematic and dimensionless way and is used to evaluate the performance of three spline polynomials and to compare them with other nu...