ISSN 2343–7707 ; ISSN-L 1453-7303

HIDRAULICA Magazine No. 4 / 2020

Hidraulica no.4/2020

Mathematics for Real-Time S-Curve Profile Generator
Authors: Marian BLEJAN, Robert BLEJAN

Position control is usually achieved using a position controller and a profile generator. The motion profile generator establishes the trajectory based on reference position and imposed motion constrains, and the position controller forces the actual position to trace the generated position trajectory. The S-curves motion profile generator allows control for the maximum values of speed, acceleration and jerk. When profile position value reaches the value of final point position, the generator sends a signal to the set-point generator to move on to next desired point of motion profile, and so on. This motion profile generator will be implemented as a software sequence which … (read more)

Automatic System for Handling Fragile Objects
Author: Ionel Laurențiu ALBOTEANU

The paper presents an automatic handling system made on a small scale. The entire structure is integrated in an electro-pneumatic drive. The handling of fragile objects is done using … (read more)

Predicting the Peak Water Level of Flood Waves by Using Statistical Methods on River Rába
Author: Gábor KERÉK

This year, as a result of a joint Hungarian-Austrian development, an early flood warning system of the Rába river basin was completed, based on hydrodynamic model support. The warning system calculates the water flows and levels with a 6-day time advantage in the defined water gauge sections of the catchment. The system also includes a 2-dimensional flood model subsystem, which models the evolution of valley floods in case of a flood wave event.
As a part of this project, an application was also implemented, which allows statistical-based parameter estimation onto flood peak levels. The basic mathematical method of this app is … (read more)

Theoretical and Experimental Researches on the Determination of Pressure Losses on Bubble Generators Used for Water Aeration
Authors: Marilena Monica BOLTINESCU (ROZA)
, Nicolae BĂRAN, Nicolae Vlad SIMA, Mihaela CONSTANTIN

The paper presents a theoretical and experimental analysis of pressure losses in the case of pneumatic aeration, which can be performed by:
A. A network of pipes with orifices arranged on the tank foundation plate
B. A system of porous diffusers
C. A network of fine bubble generators
Theoretically, the pressure loss is determined when the air passes through … (read more)

Solutions for the Reuse of Rainwater in Indoor Plumbing
Authors: Adriana TOKAR, Diana FORIȘ, Dănuț TOKAR, Simona POPA-ALBU

In agreement with lasting development and ensuring a sustainable future for administrative territorial units (ATUs) in Romania, the article proposes measures to support the environment with positive effects on natural freshwater resources and consumption. The study presents the context, necessity, and justification for plumbing modification from buildings, focused on the reduction of drinking water consumption through (read more)

Consideration on Hydraulic Modelling and Evaluation of Surface Waters with Environmental Risk
Authors: Mariana PANAITESCU
, Fănel-Viorel PANAITESCU

All groundwater catchments in a basin must be protected against pollution by establishing sanitary and hydrogeological protection areas, in order to ensure a good use of groundwater resources. The most precise method of determining the protection zones is the mathematical modeling. The paper presents a modeling of an erodible riverbed with environmental risk in (read more)

Aspects regarding the Operation of PELTON Turbine Model Used in Energy Recovery from Water Streams
Author: Fănel Dorel ȘCHEAUA

It is highlighted the major potential of natural water flows that can supply large amounts of electric energy when the necessary conditions are met regarding the water flow rate and height. In order to achieve this goal, different models of hydraulic turbines have been developed over time that are capable of taking over and using the nature provided water flow rates for the energy production. The constructive PELTON turbine type represents a special model having fixed or variable blades which can ensure an axial rotation mode when (read more)

Using the Fractional Derivative of Grundal Letnikov to Approximate the Profile of a Rectangular Channel

A two-term numerical scheme was used from the fractional derivative Grundal Letnikov, considering order a means to find the M-type profile of the water of a rectangular channel. Factors were used that associate the one-half derivative with the one-order derivative as a function of the chain x. The factors obtained from … (read more)

2D Numerical Embankment Dam Breach Modeling due to Accidental Highwaters Transitation
Authors: Marie Alice GHIȚESCU, Gheorghe I. LAZĂR, Albert Titus CONSTANTIN, Șerban-Vlad NICOARĂ

The safety in operation of the hydrotechnical constructions, in the case of the retention ones from local materials, is a particularly important issue, involving numerous technical, economic and social implications. The phenomenon of failure, an event of utmost importance, is particularly complex both in terms of genesis and development. Leaving aside the exceeding of the resistance capacity of the materials, the partial or total failures of the earth dams and / or boulders, the most numerous due to the accessible materials, can be due to infiltrations through the construction body, generating suffusions and leaks.
The paper presents a 2D numerical modeling of the liquid flow transit on the Gladna River, Timiș County, Romania, in the Surduc accumulation section, at the appearance of … (read more)

Biomass Processing from Agricultural Residual Production and Maintenance Operations when Cutting Trees and Vines
Authors: Ioan PAVEL, Gabriela MATACHE, Alexandru-Polifron CHIRIȚĂ, Alina Iolanda POPESCU, Cristian DIACONU

The article presents aspects related to the processing of biomass from agricultural secondary production, from maintenance operations when cutting trees and vines, and also an original solution of branch chopper with pulling knife through which … (read more)

Noise and Vibration Sources in Engines (Part I)
Authors: Sunny NARAYAN, Vipul GUPTA

Noise and vibrations from automotive systems form important benchmarks for customers’ choice. These have determinant effect on shelf life of engines. Hence it is important to study sources and properties of … (read more)

Noise and Vibration Sources in Engines (Part II)
Authors: Sunny NARAYAN, Vipul GUPTA

There are several sources of Noise and vibrations in automotive engines which must be controlled for proper working of engines. Combustion and motion-based noise are two important sources of noise. This work focuses on these two aspects of … (read more)

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