Forests of Japanese alder in the Russian Far East: the new association of the class Alnetea japonicae Miyawaki et al. 1977

We describe the new association Lycopo lucidi–Alnetum japonicae Korznikov, Verkholat & Krestov 2021 ass. nov. of the Alnus japonica swampy forests of the coastal plains and river valleys in the south of the Primorye Territory of Russia. The association includes two subassociations: Lycopo lucidi–Alnetum japonicae typicum Korznikov, Verkholat & Krestov 2021 subass. nov. and the preliminary delineated Lycopo lucidi–Alnetum japonicae betuletosum davuricae subass. prov. developing on gently sloping foothills with a lateral inflow of moisture and is transitional to zonal broad-leaved forests of the class Quercetea mongolicae Song ex Krestov et al. 2006. The association is classified to the alliance Fraxino–Alnion japonicae Miyawaki et al. 1977 described from Japan and belonging to the order Alnetalia japonicae Miyawaki et al. 1977 and the class Alnetea japonicae Miyawaki et al. 1977. We also validate the name of the association Stellario longifoliae–Alnetum japonicae Ohno in Miyawaki 1988 nom. inval. (art. 5) from Hokkaido Island, Northern Japan.

Influence of Different Lateral Bending Angles on the Flow Pattern of Pumping Station Lateral Inflow

A model of the pumping station lateral inflow forebay was established to explore the influence of different lateral bending angles of the pumping station lateral inflow. The lateral bending angles were set at 45° and 60°, and the two schemes were calculated separately. Analyzing the results of the numerical simulation showed that the flow patterns of the diversion passages of different schemes were good, but the advancing mainstream of the 1# inlet passage near the sidewall was seriously deviated after entering the forebay. Most of the water can flow smoothly into the inlet passage, while a small part of the water flowed into the sidewall and formed a backflow, resulting in a large-scale backflow zone near the left sidewall of the forebay. Moreover, the flow in the backflow zone was turbulent, which affected the water inlet conditions of the 1# water flow passage. Comparing the water inlet conditions of the water passage with the numerical simulation results of 45° and 60° bending angles showed that the larger the lateral bending angle of the forebay was, the worse the flow pattern of the water flow, and the more unfavorable the pump operation.

Estimation of the interaction between groundwater and surface water based on the flow routing using an improved nonlinear Muskingum-Cunge method

The interaction of groundwater (GW) and surface water (SW) not only sustains the runoff in dry seasons, but also plays an important role in regulating aquatic ecosystems. Hydrological engineers proposed the idea of modeling flood routing using the Muskingum-Cunge method. This study proposes an improved nonlinear Muskingum-Cunge flood routing model considering lateral inflow, which is denoted as NMCL1 and NMCL2 that can simulate the flood routing and calculate GW-SW exchange. In addition, both the linear and nonlinear lateral inflow (with the channel inflow) are discussed, and both the stable lateral inflow due to GW-SW exchange and the lateral inflow changing with the river inflow are considered for the first time. Sensitivity analysis has shown that different parameters have different effects on the simulation results. Three different flood cases documented in literature with one measured from Zhongtian River, China, were selected to compare the classical and the updated Muskingum-Cunge methods. Two different floods of the River Wye are selected to verify the accuracy of the calibrated model. Comparison has shown that, for several cases, the proposed method is capable of obtaining the optimal simulation results. The proposed method can estimate the GW-SW interaction and lateral inflow reliably, and inherits the ability of Maskingum-Cunge in flood routing. Moreover, the new Muskingum-Cunge method can quantify GW-SW exchange, and the estimation has reliably owned to the nonlinearity and sign flexibility of the calculated exchange process.

RETROSPECTIVE ASSESSMENT OF UNREGULATED LATERAL INFLOWS OF THE KUIBYSHEVSKY (NOW ZHIGULYOVSKAYA HYDROPOWER PLANT) HYDRAULIC UNIT OF THE VOLGA RIVER BASIN

The results of the analysis and assessment of changes in annual and seasonal characteristics of hydrometeorological processes in a private catchment area of the Kuibyshev hydroelectric complex of the Volga river are presented. To analyze the temporal dynamics of the variability of the annual and seasonal characteristics of the hydrometeorological processes in the considered territory of the river basin we used more than 100 years of observations of annual and seasonal fluctuations of lateral inflow, total atmospheric precipitation and air temperature regimes on the Volgariver. Relationship equations for annual and seasonal changes in hydrometeorological characteristics in time are obtained. It was found that long-term fluctuations of hydrometeorological processes (lateral inflow, total atmospheric precipitation and air temperature) are characterized by tendencies (trends). The analysis of these trends showed that the non-standard climatic situation, starting from the 70s of the last century, had a very significant impact on the distribution of annual and especially on the seasonal (low-water and winter) characteristics of hydrometeorological processes. It has been established that non-standard unidirectional changes are found in the fluctuations in the total atmospheric precipitation. If the winter total precipitation is characterized over the 100-year period in question by a continuously decreasing trend,the summer-autumn period is an increasing trend. This leads to the fact that long-term fluctuations in total precipitation during the period of low water are formed as a stationary process. At the same time, the total precipitation of the spring flood and inflowing to the Kuibyshev hydroelectric unit is characterized by a constantly increasing trend.

Understanding the Effect of Rotor-to-Rotor Interference on CH-47D Helicopter Dynamics

During the development of the Boeing CH-47D helicopter flight simulation model, test pilots reported mismatch between the flight simulator results and flight test data of the hover and low-speed lateral axis handling qualities, especially for the case without the automatic flight control system. In addressing the observed mismatch, the gains of the longitudinal and lateral components of the inflow model were selected to be significantly higher than their theoretical values. In this study, a detailed understanding of the rotor-to-rotor inflow interference is pursued using a recently developed multi-rotor pressure potential superposition inflow model. It is shown that the coupling between the inflow gradients of individual rotors exists in a tandem rotor, which can be approximated by using higher values for the longitudinal and lateral inflow gains of individual rotors. Further, it is shown that the need for empirical tuning of aerodynamic hub moment influence factors can be eliminated by properly accounting for the rotor-to-rotor interference in the inflow model.

Physicochemical characterization of the unconfined water-table aquifer of the Fez-Meknes basin

This paper aims to determine the hydrogeochemical characteristics of the Fez-Meknes free water table thought the monitoring of the physicochemical analyses of nine samples during the year of 2013, 2016, and 2019. This water table, which circulates in the plio-quaternary formations, is generally supplied by rainfall infiltration, irrigation water returns and also the lateral inflow of the unconfined liasic water table of the Middle Atlas Tabular. Analyses were performed for electrical conductivity (EC), potential hydrogen (pH), temperature and major elements: Cl-, NO3-, SO42-, Na+, Mg2+, Ca2+, HCO3⁻, K+. The results of the projection of the samples on the Piper diagram for the three companies showed a hydrochemical carbonate, calcic and magnesian facies for the majority of the samples with the exception of samples 1161/15 and 352/21 for the year 2013. Then, to understand the origin of the mineralization, as well as the processes related to the dissolution of the carbonate country rock, a principal component analysis (PCA) was performed.

Comparison and verification of turbulence Reynolds-averaged Navier–Stokes closures to model spatially varied flows

The robustness and accuracy of Reynolds-averaged Navier–Stokes (RANS) models was investigated for complex turbulent flow in an open channel receiving lateral inflow, also known as spatially varied flow with increasing discharge (SVF). The three RANS turbulence models tested include realizable k–ε, shear stress transport k–ω and Reynolds stress model based on their prominence to model jets in crossflows. Results were compared to experimental laser Doppler velocimetry measurements from a previous study. RANS results in the uniform flow region and farther from the jet centreline were more accurate than within the lateral inflow region. On the leeward side of the jet, RANS models failed to capture the downward velocity vectors resulting in major deviations in vertical velocity. Among RANS models minor variations were noted at impingement and near the water surface. Regardless of inadequately predicting complex characteristics of SVF, RANS models matched experimental water surface profiles and proved more superior to the theoretical approach currently used for design purposes.

On characteristic hydraulic times through hydrodynamic modelling: discussion and application in Patos Lagoon (RS)

Although the analyses of characteristic hydraulic times are important diagnostic tools for studying water mass exchanges and identifying areas prone to stagnation that are potentially subjected to eutrophication effects, their concepts and uses are often misinterpreted. This paper compares similarities and differences between widely used characteristic hydraulic times, CHT, known as Residence Time, Times of Water Renewal Rates and Water Age. A proper definition for each of these characteristic hydraulic times is stated to avoid the existing confusion with multiple concepts in the literature. Methodologies to compute these CHT through hydrodynamic modelling systems are presented and, in order to enhance understanding, applied to three idealized cases in steady flow channels: (1) Channel with uniform flow; (2) Channel with a lateral inflow; and (3) Channel with a lateral embayment. Finally, a practical example is discussed by applying the methodologies to the Patos Lagoon (RS). The results for the idealized channel cases are non-intuitive and this theoretical discussion clarifies the interpretation and uses of different timescales and outlines the Water Age as the more versatile and multifunctional timescale if compared to the others addressed here. The results for the Patos Lagoon exemplify the valuable information that CHT can offer for environmental management in natural water bodies.