Papers by Franci STEINMAN
European Journal of Mechanics B-fluids, May 1, 2020
Laser ranging is a measurement method, applied in a wide range of applications. In this study, la... more Laser ranging is a measurement method, applied in a wide range of applications. In this study, laser ranging is used to measure the height of turbulent water flows. Measurements were performed in three cross sections of a confluence where a tributary flow meets the main flow. Both flows exhibited high Reynolds and Froude numbers where the free-water surface profiles were turbulent, non-stationary and non-homogeneous. Measurements were taken using a commercial LIDAR and a high-speed camera. The high-speed camera was operated on the principle of laser triangulation, using only the illumination from the LIDAR laser beam. Since, no other state-of-the-art method for measuring instantaneous water surface profiles exists, LIDAR and triangulation methods could only be compared with each other. The results show good agreement between both methods for the average turbulent water profile and fair agreement for instantaneous profiles. Presented herein is an explanation of these results.
Flow Measurement and Instrumentation, Mar 1, 2013
The purpose of the research was to quantify characteristics of a subcritical flow at a rectangula... more The purpose of the research was to quantify characteristics of a subcritical flow at a rectangular sharpcrested side weir in a rectangular main channel using non-invasive measuring techniques based on the visualization of the flow. Experiments were carried out in physical models, including nine different dimensions of the side weir and nine combinations of the inflow and tailwater level for each weir, amounting to 81 test runs. Velocity vector fields were measured in various horizontal planes along the side weir using a high speed digital camera and electrolysis-induced hydrogen bubbles as flow tracers. Recorded films were converted into sequences of images which were used for numerical calculation of local velocities. Components of velocity vectors were determined with great spatial and time resolution. Longitudinal profiles of water surface elevation at each side weir were determined using photos of laser-induced vertical section planes. Measured discharges and flow depths were used to formulate new equation for the side weir discharge coefficient using dimensional analysis. The principal results indicated that velocity distribution along the side weir was distinctly non-uniform, with various velocity ratios increasing along the crest. However, the calculated energy grade line was parallel to the main channel bed, indicating that only friction losses were present. The proposed equations for the side weir discharge coefficient gave results that were in good accordance with two other studies.
EGU General Assembly Conference Abstracts, Apr 1, 2019
Proceedings of the 39th IAHR World Congress
Journal of Flood Risk Management, 2021
This study proposes to adopt the Hazard Analysis Critical Control Point (HACCP) approach and its ... more This study proposes to adopt the Hazard Analysis Critical Control Point (HACCP) approach and its seven principles to assist integrated flood management and transboundary cooperation in river basins, extending over more municipalities, regions, or states. Although HACCP was initially employed in the food production and processing industry to identify hazards and reduce risks throughout the production process, its principles have already been successfully applied to other sectors, such as water supply and wastewater treatment. The paper focuses (a) on the adaptation of the HACCP approach for integrated flood management, for example, for assessing the impact of planned upstream measures on downstream areas, and (b) on step 3 of the proposed Flood‐HACCP approach establishing critical limits for CCPs. For the demonstration purposes, the confluence of the Slovenian part of Drava River and its tributaries, Meža and Mislinja, is selected. Results indicate that keeping the Meža River discharge within the range of ±5% from its initial value would cause only minor local changes of flood situation within the selected case study area. On the other hand, variations to the Mislinja River discharge could change the flood situation to a greater extent and in a more diffuse way.
Measurements of water surface topography are important for hydraulic structures, operation of hyd... more Measurements of water surface topography are important for hydraulic structures, operation of hydropower plants as well as in the determination of water surface profiles in rivers, especially in the event of high waters. We therefore investigated the conditions at a confluence of two supercritical flows, where distinctly three-dimensional flow conditions of standing waves form, as well as an unsteady structure of the water flow in transversal and longitudinal directions. Due to the fast water surface dynamics and the phenomenon of foamed or twophase flow, the conventional measurement methods typically used in hydro engineering are not suitable for capturing complex water surface topography with high temporal and spatial resolution. Hence we wanted to verify the appropriateness of the laser scanning method for water surface topography measurements. This measurement method, which is considered less suitable or even useless for measurements of water body surfaces, was, coupled with an ...
Flow Measurement and Instrumentation, 2017
Abstract Measuring the topography of water surfaces with conventional measurement methods is, par... more Abstract Measuring the topography of water surfaces with conventional measurement methods is, particularly in the case of turbulent flow with strong vertical and longitudinal dynamics, a very demanding and challenging task. Channel confluences are important elements in river engineering, as they appear in natural and regulated river channels, torrents, as well as in numerous hydraulic structures. At confluences, especially in the case of incoming supercritical flow, turbulent three-dimensional flows occur, and a time-varying structure of waters surface. Laser scanning enables data capture with high spatial and temporal resolution, and this method is widely used nowadays. This article discusses laser scanning as a measurement method for acquiring the agitated shape of a water surface. The application of a commercial two-dimensional LIDAR device for free-water-surface acquisition is presented for two cases. In the first case the measurements were performed in a glass tank where it was possible to determine the precise reference water level. In the second case we used LIDAR with turbulent aerated flow for fluctuating free-water surface measurement. Measurements were taken in the model of supercritical confluence, where the development of standing waves leads to the phenomenon of self-aerated flow. The measurements presented in the paper were conducted for a selected discharge rates and the Froude numbers of the main and side flow channels. Measurement results are shown as surface profiles at several selected locations of confluence. This measurement method has proven to be very promising.
Decision Support for Natural Disasters and Intentional Threats to Water Security, 2009
There are more than 1,000 water supply systems (WSS) in the Republic of Slovenia due to the dispe... more There are more than 1,000 water supply systems (WSS) in the Republic of Slovenia due to the dispersed settlement pattern and more than 120 WSS operators managing them. In order to follow-up the performance of public service on all those systems and ensure the efficiency of the managing companies a complex regulative system (with decision support system-DSS) is under continuous development with a scope to ensure safe and quality water supply on short term as well on long term. The driving mechanism for DSS was implementation of the EU Drinking Water Directive. A specific topic in this DSS is now addressing also the functionality of water supply system as critical infrastructure under terms of forthcoming EU Directive (proposed COM 2006/787) and national. Within the annex I of the proposed Critical Infrastructure Directive-Provision of drinking water and control of water quality water supply is identified as one of the explicitly listed sub-sectors. While the proposed directive is generally addressing the infrastructure that affects two or more member states it is also clearly expressing necessity of close harmonization with national systems of critical infrastructure. In the article the applied approach on the DSS level to the critical infrastructure will be presented with key steps that are foreseen by the directive: identification of the infrastructure, risk analysis, countermeasures and procedures implemented in the system.
Managing Water: Coping with Scarcity …, 1996
... CE Database Search | Descriptions | Search Tips | Subject Heading List. Slovenian Water Manag... more ... CE Database Search | Descriptions | Search Tips | Subject Heading List. Slovenian Water Management Strategy - Towards EU Water Pology. by Franci Steinman and Primoz Banovec pp. 375-380 Purchase Information Permissions for Reuse ...
European Journal of Mechanics - B/Fluids, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Strojniški vestnik – Journal of Mechanical Engineering, 2015
Chemical Engineering Journal, 2011
Chemical Engineering and Processing: Process Intensification, 2013
The performance of secondary clarifiers is strongly related to density effects in the sedimentati... more The performance of secondary clarifiers is strongly related to density effects in the sedimentation vessel. The upper level of the clarifier's chamber-once considered to be inactive at the sedimentation processnow appears to play an important role in solids removal. A fully developed three-layer flow phenomenon that develops in some cases is proved to promote settling. Therefore, investigation of flow patterns at different operative conditions was carried out. Experiments were conducted in a model of a circular, centre-feed settling tank with continuous operation. Ground hazelnut shells served as the settling matter; in one set of experiments only dye was used. All laboratory runs were filmed and analysed, qualitatively and quantitatively, by means of computer-aided visualisation. The results of the study showed that a determining factor of the conditions favourable for formation of a fully developed three-layer flow is the theoretical densimetric Froude number. If the hydraulic and solid loadings are soundly chosen in accordance with these findings, the clarifier performance can be evidently improved.
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Papers by Franci STEINMAN