Characteristics of the Exchange Flow of the Bay of Quinte and Its Sheltered Embayments with Lake Ontario

The nature of the exchange flow between the Bay of Quinte and Lake Ontario has been studied to illustrate the effects of the seasonal onset of stratification on the flushing and transport of material within the bay. Flushing is an important physical process in bays used as drinking water sources because it affects phosphorous loads and water quality. A 2-d analytical model and a 3-dimensional numerical coastal model (FVCOM) were used together with in situ observations of temperature and water speed to illustrate the two-layer nature of the late summer exchange flow between the Bay of Quinte and Lake Ontario. Observations and model simulations were performed for spring and summer of 2018 and showed a cool wedge of bottom water in late summer extending from Lake Ontario and moving into Hay Bay at approximately 3 cm/s. Observed and modelled water speeds were used to calculate monthly averaged fluxes out of the Bay of Quinte. After the thermocline developed, Lake Ontario water backflowed into the Bay of Quinte at a rate approximately equal to the surface outflow decreasing the flushing rate. Over approximately 18.5 days of July 2018, the winds were insufficiently strong to break down the stratification, indicating that deeper waters of the bay are not well mixed. Particle tracking was used to illustrate how Hay Bay provides a habitat for algae growth within the bay.

Learning and detecting abnormal speed of marine robots

This article presents anomaly detection algorithms for marine robots based on their trajectories under the influence of unknown ocean flow. A learning algorithm identifies the flow field and estimates the through-water speed of a marine robot. By comparing the through-water speed with a nominal speed range, the algorithm is able to detect anomalies causing unusual speed changes. The identified ocean flow field is used to eliminate false alarms, where an abnormal trajectory may be caused by unexpected flow. The convergence of the algorithms is justified through the theory of adaptive control. The proposed strategy is robust to speed constraints and inaccurate flow modeling. Experimental results are collected on an indoor testbed formed by the Georgia Tech Miniature Autonomous Blimp and Georgia Tech Wind Measuring Robot, while simulation study is performed for ocean flow field. Data collected in both studies confirm the effectiveness of the algorithms in identifying the through-water speed and the detection of speed anomalies while avoiding false alarms.

Information support for the procedure of measuring the flow rate of water in open channels by a water current meter with Arduino Micro board

The modernization of a typical water current meter is proposed to facilitate hydrological observations on natural and artificial open watercourses. An Arduino Pro Micro microcontroller board was used to read the speed of the current meter and primary data processing, programs were developed: for the lower level - a microcontroller located on the board, and for the upper level - a smartphone to determine the water speed. The programs take into account the peculiarities of converting data on the flow rate of water with a current meter and allow you to enter additional indicators that reduce the uncertainty of the results.

The effect of multi-stage modification on the performance of Savonius water turbines under the horizontal axis condition

Indonesia has the abundant potential of hydropower but not yet processed optimally, which intensely depends on fossil fuel. Hydropower installed in Indonesia is only 11,272 MW, from the estimated potential approximately 94,476 MW. This data shows that 89% of the hydropower potential in Indonesia has not been processed. One of the present efforts to utilize this resource is addressed to develop the Savonius water turbine. Conventional water Savonius turbines have a comprehensible structure and easy to be applied. However, the turbines produce relatively small power, which requires further assessment to improve its performance. The current study is performed by considering geometric changes on the water Savonius turbine to observe their effect on power characteristics. Considered changes are made on the number of stages, and the angle between stages, specifically a single-stage, two-stage 0°, Two-stage 90°, three-stage 0°, and three Stage 120°. The research was carried out by designing simulation model using ANSYS software with CFX Solver. Water speed is determined to 0.8 m/s, while plates with 110 mm in diameter and 110 mm in height are incorporated as rotor configuration. Based on this study, it can be concluded that the addition of the stage affected improving the performance of the Savonius water turbine, where the multi-stage turbine experienced an increment compared to conventional water turbines. The interesting tendency was found on the two-stage rotors with angle of 0° which produced a smaller Cpmax compared to the conventional water Savonius turbines.

System-Based Modelling of KCS Manoeuvring in Calm Water, Current and Waves

Maritime autonomous surface ships (MASS) require accurate future state projection to initiate collision-avoidance manoeuvres. Forecasts of the vessels’ trajectories and motions are fundamentally based on the mathematical manoeuvring model, which is an essential component of their hydrodynamic digital twin nowadays. Using the benchmark container ship KCS as an object of study, this paper adopts a 4-DOF modular-type manoeuvring (MMG) model to predict the vessel trajectories in calm water and under the presence of steady current and regular waves. The current effects are treated as additional ship over water speed, while the wave effects are considered by superimposing the second-order mean wave drift loads to the calm water hull hydrodynamics. The wave drift loads are solved using the potential flow solver WASIM, which is based on Rankine panel method. The computed vessel trajectories and motions are compared with available literature results and show good correlation.

To the question of variability of number of micropyles in oocytes of ship sturgeon (Acipenser nudiventris)

The paper considers the characteristics of the gametes, habitats and spawning conditions of sturgeon, which are important for improving the biotechnology of their artificial reproduction. Based on the native data and literature, there have been analyzed the limits of variation of micropyle of ship sturgeon (Acipenser nudiventris Lovetsky, 1828) and some other species, as well as the features of the micropylar complex. The material for the study conducted in 2018-2019 served the ovulated eggs and caviar from the broodstock of the second-third generation of ship sturgeon, which contained in the conditions of the State Regional Centre for Sturgeon Gene Pool Conservation “Kubanbioresursi”. Ship sturgeon has been found to have the largest average number of micropyles among low-chromosomal species. In the main sample, the number of micropyles varied from 2 to 41, with an average value of 11.09 ± 0.24 and a concentration of indicators from 2 to 19 (94%). The location peculiarity and a slight variation in the number of micropyles in one female species of ship sturgeon have been revealed, as well as the different shape of a micropylar complex, as opposed to the similar shapes in other sturgeon species: ship sturgeon has not the funnel-shaped micropylar complex, but the bowl-shaped one. The ship sturgeon spawns under conditions of high water speed and a micropylar bowl, the diameter of which exceeds 2-3 times the diameter of the funnel and increases the collection area of the highly diluted seminal fluid. From a practical point of view, studying these features is important for improving the biotechnology of artificial insemination of roe of rare species in conditions of almost complete absence of natural reproduction in natural conditions.

Initial Alignment of Shipborne SINS under Ship Motion

The paper focuses on improving the accuracy and shortening the time of shipborne SINS initial alignment under the ship yaw, roll and pitch. This is achieved by implementing a two-step SINS alignment algorithm. At the first step, the ship current attitude parameters are approximately autonomously estimated by data from gyros and accelerometers with account for its dynamics and using water speed log data. At the second step, the system fine alignment is performed with account for alignment errors after the completion of the first step. Speed and position measurements from external aids are additionally applied during the fine alignment. Kalman filter algorithms are used in the first and second steps. Results from bench and sea tests for SINS on navigation grade FOGs under the ship yaw, roll and pitch motion are provided.

Multiple Model Algorithm for Single-Beacon Navigation of Autonomous Underwater Vehicle without Its A Priori Position. Part 2. Simulation

The algorithm presented earlier is updated for the case when an autonomous unmanned vehicle (AUV) is equipped with a strapdown inertial navigation system (SINS) based on angular rate sensors and a water speed log. The algorithm simulation results for a SINS of navigation grade, a two-component water speed log, two trajectories of the AUV motion when approaching the beacon to a distance of 100 m; two values of the AUV’s speed; solid and fragmented diagrams of received acoustic measurements are presented. The results show that the algorithm provides the AUV positioning accuracy of several meters even in the situations when the received acoustic measurements are discontinuous. It has been found that the accuracy characteristics provided by the algorithm adequately reflect the level of real errors.