ANALYSIS OF THE RESULTS OF PERFORATED DRAINAGE PIPELINES CALCULATION IN THE PRESENCE OF TRANSIT FLOW RATE

A method of calculating the error that occurs when determining the flow rate in the final section of the pressure perforated drainage pipeline when it passes transit flow rate, based on the analysis of differential equations describing the fluid motion with variable flow rate in such pipelines is proposed in the paper. The analysis is presented in dimensionless form. The impact of transit flow on the main flow is estimated using the values ​​of the drainage pipeline resistance coefficient ζl and the generalized parameter of the perforated drain A, which takes into account its constructive and filtration characteristics. The obtained calculation formulas are quite simple and easy to use. The proposed method allows to perform calculations of drainage pipelines that operate in the presence of transit flow rate, according to the method of these pipes calculation that dispose drain water without passing transit. Herewith, the possible error, which includes in the calculation results, determines. To illustrate the obtained dependences, the corresponding graphs are given in the paper. The results of the analysis allow to determine the limits within which a simplified method of calculating these pipes can be used and the error, that occurs, can be estimated

Modeling Transit Flow Through Port Gates and Connecting Channel in Baltic Sea—Liepaja Port—Liepaja Lake System

This study investigates a water transport features by extending Copernicus Marine Environment Service (CMEMS) to the Liepaja coast-port-channel-lake system with a two-way nested model. The Liepaja lake and Liepaja port are connected by Trade channel. The Liepaja port has three gates—the openings in wave breakers connecting the port aquatory with the Baltic sea. Each of gates has a corresponding dredged channel for securing the navigation. A hydrodynamic model is set up to study the flow and water level in this system. The area of the port gates, port and Trade channel are resolved by 33 m grid. The model results are verified against currents and sea level observations inside/outside port, Trade channel and Liepaja lake. Results and observations show that strong currents occur in the Trade channel in case of rapid sea level change in Baltic sea despite the Trade channel is rather shallow at the connection with Liepaja lake. The northern part of the Liepaja lake gets filled with brackish water during storm surge events. The channel has notable alternating current also during a relatively calm weather due to the port seiches. Long and narrow shape of the channel implies the Helmholtz type oscillations between the lake and the port with a period in approximately semidiurnal range. Hydrodynamic simulations describe well these oscillations but the phase of hourly scale oscillations in the port may differ in case of weak external forcing. Water exchange is significantly increased by the transit (gate to gate) sea currents. This transit flow usually occurs between South or Central gate and the North gate carrying sea water into the port. Northward flow of the surface layer is more characteristic in the port aquatory due the prevailing south-western winds. There are intense morphological processes at the coastline and underwater slope near the Liepaja port due to a sandy western coastline of Latvia, long fetch of the waves and strong currents at the port gates. Liepaja port is one of the Latvian ports in HywasPort operational service of hydrodynamics, waves and siltation.

Rational areas of combined transport technologies application for container delivery on the Caspian-Black sea route of the new Silk Road

The article analyzes the main routes for delivering goods from China to the EU countries. The main transit flow in this direction is cargo in containers. The competitive Caspian-Black Sea route of the New Silk Road through Ukraine with the use of combined rail and sea transportations has been analyzed. Two delivery options are considered – using ferry ship and feeder ship lines. Simulation was used to evaluate the route parameters. Recommendations on the rational areas of combined transport technologies application on this route are given.

Water loss in transit in an intermittent river in brazilian semi-arid

Riverwater often comes into contact with the underground flow in aquifers. When this contact occurs, the river and aquifer are considered to be hydraulically connected. In recent decades, there has been great interest in trying to to improve understanding of the interactions occuring between superficial and subterranean water systems. A variety of analytical solutions have been proposed to describe the interaction of confined and free aquifers with adjacent rivers, including the quantification of the decrease of river flow along its course. The objective of the current study was to calibrate and validate a loss-in-transit flow model for rivers, and to evaluate the minimum flow that still permits connectivity between water sources in the Alto Jaguaribe basin. The methodology used was based on the equation of continuity and mass balance along the study river. A modified Araújo and Ribeiro equation showed strong applicability to loss-in-transit generation, with a mean loss in transit of 3.6% km-1, and a Nash and Sutcliffe Efficiency value of 0.29. On the other hand, the classbased loss of upstream flow generated 4 classes with a mean of 2.6% km-1 and showed great improvement, reaching an NSE of 0.74 - high efficiency. Minimum flows were below the regular flow recorded by the Ceará Secretariat of Water Resources, showing that the ability exists in the region hydrological connectivity between reservoirs in the Alto Jaguaribe basin and for alluvial aquifers to be recharged.

Influence of transit water flow rate on its dispensation and on inflow through nozzles in pressure pipeline under action of external pressure

The influence of transit flow rate of water upon operative of the equipped with nozzles pressure pipeline is experimentally investigated. External pressure, which varies in the range of 1465-2295 mm, acted upon the pipeline. The angle β between vectors of velocities of the stream in the pipeline and jets which branch off through nozzles were given the value: 0° ; 45° ; 90° ; 135° ; 180°. The diameter of the pipeline was of D=20.18 mm, the diameter of nozzles d=6.01 mm. The distances between the nozzles were 180 mm, and the number of them 11. The value of the transit flow rate at input into the pipeline varied from 4.05 to 130.20 cm3 / s. The increase in flow rate of the transit flux Qtr caused increase in non-uniformity of distribution of operating heads and increase in flow rate of water along the pipeline over the segment of its dispensation. On the segment of collecting of water, inverse tendency was observed. The number of nozzles through which water became to be dispensed increased with the increase in Qtr.