The Use of Acrylic as a Structural Material in the Design of Translucent Elements of Deep-Submergence Vehicles

2021 ◽  
Vol 1031 ◽  
pp. 196-200
Author(s):  
Natalya A. Gasratova ◽  
Victor S. Zuev
Keyword(s):  
Experimental Data ◽  
Structural Material ◽  
Characteristic Feature ◽  
Deep Sea ◽  
Underwater Vehicle ◽  
Strength Analysis ◽  
Present Stage ◽  
Significant Difference ◽  
External Conditions ◽  
Main Characteristic Feature

The exploration of the depths of the sea is an activity that is important for many branches of science; it is associated with the work of people and technology in extremely difficult external conditions, which, in their extremeness, are comparable, perhaps, only with the conquest of space. At the present stage, deep-sea surveys are carried out using various instruments, including manned ones. These machines do not belong to the class of military large-tonnage submarines, but to the so-called Bubble Subs. The hull, which is a translucent thick-walled spherical shell is the main characteristic feature of this type of underwater vehicle. The presented work lists the main problems faced by researchers in the strength analysis of such PMMA hulls. In particular, the issue of the significant difference between the results of calculations in cases where the material is considered as physically linear and as physically non-linear is disclosed in detail. In addition, the obtained numerical results are compared with the experimental data.

Drag Analysis of Contractile Water Jet Locomoted Micro AUV in Laminar Fluid

2015 ◽  
Vol 799-800 ◽  
pp. 1188-1192
Author(s):  
Muhammad Farid Shaari
Keyword(s):  
Experimental Data ◽  
Autonomous Underwater Vehicle ◽  
Dynamic Pressure ◽  
Underwater Vehicle ◽  
Water Jet ◽  
Surface Drag ◽  
Simulation Data ◽  
Total Drag ◽  
Significant Difference ◽  
Drag Analysis

Drag analysis is vital to measure the performance of the autonomous underwater vehicle (AUV) as well as the AUV thruster. Most of the previous drag studies is regarding to the shape and swimming method that contribute to the AUV performance. However, few attention was given on drag which influence the development of thruster. Hence, this research was conducted to analyze the drag of the micro AUV in a laminar fluid flow in order to find the optimum thrust that must be gained by a contractile water jet thruster (CWJT). Besides, these studies also focus on the dynamic pressure and skin friction that forms the total drag which acted on the AUV surface. Drag was measured by using pull technique and simulation technique for AUV speed below 0.5ms-1. The results show that the recorded drag was between 9.0 x 10-4N and 1.8 x 10-1N. The trend line between the simulation data and experimental data has no significant difference and thus it shows that the simulation data were verified. Both results exhibits that the drag increase tremendously regarding to the AUV speed increment.

scholarly journals Elaboration of the Equipment and Technology for Cutting Rolled Round Bars and Pipes with the Cyclic Circular Bending Method

2021 ◽  
Vol 346 ◽  
pp. 01011
Author(s):  
Aleksej Antimonov ◽  
Sergej Poljanskij ◽  
Nadezhda Pushkareva
Keyword(s):  
Experimental Data ◽  
Low Cycle Fatigue ◽  
Continuous Process ◽  
Comparative Assessment ◽  
Strength Analysis ◽  
Cyclic Loads ◽  
Cycle Fatigue ◽  
Significant Difference ◽  
Theoretical Assessment ◽  
Good Agreement

A brief overview of methods for cutting round bars and pipes is presented, their main advantages, disadvantages and field of application are considered. It is proposed to use the effect of fatigue fracture for round bars and pipes breaking. The task is to study this process under the action of cyclic loads. The possibility of applying the known provisions of calculating theory of strength analysis for low-cycle fatigue for this process is tested. A comparative assessment of theoretical and experimental data is given and their significant difference is established. New calculated dependences are proposed, which are in good agreement with the experimental data. A theoretical assessment of the productivity of the process of round bars and pipes breaking by the method of cyclic circular bending was carried out using new results and various options for the design of a device for breaking were considered with an analysis of the features of their operation. Based on the results of the analysis, a variant of the device for the implementation of a continuous process of breaking the pointed ends of thick-walled fuel pipes during drawing in coils and a diagram of the mechanism for breaking the ends of the pipe with its supply from the coil were selected. Samples of pipes obtained by brittle cyclic bending are presented.

Comparison of soot models for reacting sprays in diesel engine-like conditions

2021 ◽  
pp. 095440702110154
Author(s):  
Pavan Prakash Duvvuri ◽  
Rajesh Kumar Shrivastava ◽  
Sheshadri Sreedhara
Keyword(s):  
Experimental Data ◽  
Volume Fraction ◽  
Soot Volume Fraction ◽  
Modeling Framework ◽  
Aerosol Dynamics ◽  
Significant Difference ◽  
Polycyclic Aromatic ◽  
Order Of Magnitude ◽  
Detailed Kinetics ◽  
Soot Model

Stringent emission legislations and growing health concerns have contributed to the evolution of soot modeling in diesel engines from simple empirical relations to methods involving detailed kinetics and complex aerosol dynamics. In this paper, four different soot models have been evaluated for the high temperature, high pressure combusting dodecane spray cases of engine combustion network (ECN) spray A which mimics engine-relevant conditions. The soot models considered include an empirical, a multistep, a method of moments based, and a discrete sectional method soot model. Two experimental cases with ambient oxygen volume of 21% and 15% have been modeled. A good agreement between simulations and experiments for vapor penetration and heat release rate has been obtained. Quasi-steady soot volume fraction contours for the four soot models have been compared with experiments. Contours of the species and source terms involved in soot modeling have also been compared for a better understanding of soot processes. The empirical soot model results in higher magnitude and spread of soot due to a lack of modeling framework for oxidation through OH species. Among the four models studied, the multistep soot model has been observed to provide the most promising agreement with the experimental data in terms of distribution of soot and location of peak soot volume fraction. Due to a two-way coupling of soot models, the detailed models predict an upstream location for soot as compared to the multi-step soot model which is one way coupled. A significant difference (of an order of magnitude) in the concentration of PAH (polycyclic aromatic hydrocarbons) precursor between multistep and detailed soot models has been observed because of precursor consumption due to the coupling of detailed soot models with chemical kinetics. It is recommended that kinetic schemes, especially those concerning PAH, be validated with experimental data with a kinetics-coupled soot model.

Difference in Critical Reynolds Number Between Hagen-Poiseuille and Plane Poiseuille Flows

2001 ◽  
Author(s):  
Hidesada Kanda
Keyword(s):  
Experimental Data ◽  
Reynolds Number ◽  
Poiseuille Flow ◽  
Average Velocity ◽  
Critical Reynolds Number ◽  
Inlet Section ◽  
Parallel Plates ◽  
Plane Poiseuille Flow ◽  
Contraction Ratio ◽  
Significant Difference

Abstract For plane Poiseuille flow, results of previous investigations were studied, focusing on experimental data on the critical Reynolds number, the entrance length, and the transition length. Consequently, concerning the natural transition, it was confirmed from the experimental data that (i) the transition occurs in the entrance region, (ii) the critical Reynolds number increases as the contraction ratio in the inlet section increases, and (iii) the minimum critical Reynolds number is obtained when the contraction ratio is the smallest or one, and there is no-shaped entrance or straight parallel plates. Its value exists in the neighborhood of 1300, based on the channel height and the average velocity. Although, for Hagen-Poiseuille flow, the minimum critical Reynolds number is approximately 2000, based on the pipe diameter and the average velocity, there seems to be no significant difference in the transition from laminar to turbulent flow between Hagen-Poiseuille flow and plane Poiseuille flow.

Numerical Simulation of a Jumper Conveying Slurry for Deep-Sea Mining

2021 ◽  
Author(s):  
Marcio Yamamoto ◽  
Tomo Fujiwara ◽  
Joji Yamamoto ◽  
Sotaro Masanobu
Keyword(s):  
Experimental Data ◽  
Pressure Drop ◽  
Dynamic Analysis ◽  
Internal Pressure ◽  
Deep Sea ◽  
Petroleum Industry ◽  
Vertical Direction ◽  
Internal Flow ◽  
Horizontal Direction ◽  
Viscous Pressure

Abstract One key technology for Deep-Sea Mining is the riser system. The riser is already a field-proven technology in the Petroleum Industry. However, several differences exist between a petroleum production riser and a riser for Deep-Sea Mining, mainly related to the internal flow. The ore-slurry has a larger density than the hydrocarbons and shall be pumped with a much higher flowrate. The current software tools for riser’s dynamic analysis may include the internal fluid hydrostatic pressure and the centrifugal and Coriolis forces imposed by the bent pipe’s internal flow. However, the internal pressure drop is not calculated. The internal pressure alters the pipe’s effective tension and can alter the pipe’s bending moment changing its mechanical behavior. This article describes a computational script’s development to run embedded in a commercial software for riser’s dynamic analysis. Our script calculates the internal viscous pressure drop along with the jumper. This pressure is then converted into wall axial tension (buckling) and imposed on each node of the jumper’s numerical model. Each simulation case was calculated twice with and without the internal flow viscous pressure drop. The comparison with experimental data revealed that the jumper’s average position has a good agreement among all cases. However, the amplitude caused by the top oscillation showed some discrepancies. Experimental data has the highest amplitude in the horizontal direction, while the simulation without viscous pressure calculation had the smallest. The simulation with our embedded script had intermediary amplitude in the horizontal direction. The vertical direction amplitudes have the same behavior for all cases, but the experimental data showed the highest amplitude.

scholarly journals Adenosine Triphosphate Measurement in Deep Sea Using a Microfluidic Device

Micromachines ◽  
2018 ◽  
Vol 9 (8) ◽  
pp. 370 ◽  
Author(s):  
Tatsuhiro Fukuba ◽  
Takuroh Noguchi ◽  
Kei Okamura ◽  
Teruo Fujii
Keyword(s):  
Adenosine Triphosphate ◽  
Microfluidic Device ◽  
Deep Sea ◽  
Temperature Sensor ◽  
Biochemical Parameter ◽  
Underwater Vehicle ◽  
Luciferase Assay ◽  
Bioluminescence Intensity

Total ATP (adenosine triphosphate) concentration is a useful biochemical parameter for detecting microbial biomass or biogeochemical activity anomalies in the natural environment. In this study, we describe the development and evaluation of a new version of in situ ATP analyzer improved for the continuous and quantitative determination of ATP in submarine environments. We integrated a transparent microfluidic device containing a microchannel for cell lysis and a channel for the bioluminescence L–L (luciferin–luciferase) assay with a miniature pumping unit and a photometry module for the measurement of the bioluminescence intensity. A heater and a temperature sensor were also included in the system to maintain an optimal temperature for the L–L reaction. In this study, the analyzer was evaluated in deep sea environments, reaching a depth of 200 m using a remotely operated underwater vehicle. We show that the ATP analyzer successfully operated in the deep-sea environment and accurately quantified total ATP within the concentration lower than 5 × 10−11 M.

scholarly journals Quantification of mantle attachment scars on the Margaritifera margaritifera (Margaritiferidae, Bivalvia) shell

2019 ◽  
Vol 19 (2) ◽  
pp. 81-86
Author(s):  
A. A. Zotin ◽  
E. P. Ieshko
Keyword(s):  
Factor Analysis ◽  
Characteristic Feature ◽  
Species Identification ◽  
Internal Surface ◽  
Regression Coefficients ◽  
Margaritifera Margaritifera ◽  
Shell Surface ◽  
Significant Difference ◽  
Mollusc Species ◽  
Quantitative Indicators

A characteristic feature shared by all Margaritiferidae mussels consists in the presence of scars on the internal surface of their shells. These scars mark places of mantle attachment by specific epithelial cells. According to some authors, such parameters of mantle attachment scars as the density and degree of their manifestation can be used for the purposes of species identification. To this end, quality indicators (numerous or few, pronounced or poorly visible scars) are typically used; however, the use of quantitative criteria is preferable. This work was aimed at developing quantitative indicators of mantle attachment scars in the Margaritifera margaritifera freshwater pearl mussels for the populations of the Syuskyuyanyoki and Livoyoki rivers (Karelia). It is shown that the density and size of mantle attachment scars are approximately the same for all the investigated shell samples. These parameters display the absence of dependence on the age and size of molluscs. The regression coefficients for the linear dependence of the density or size of mantle attachment scars on the age or length of the shell show no significant difference from 0. For all the investigated molluscs, the density and size of mantle attachment scars are established to vary within the range of 0.37–1.16 scars/cm2 (0.71 ± 0.03 scars/cm2 on average) and 215–690 µm (417 ± 2 µm on average), respectively. According to a two-factor analysis of variance, the distribution of mantle attachment scars appears to be irregular across the shell surface. At the same time, a significant (p < 0.001) increase in their density is observed in the posterior and ventral directions, as well as diagonally in the posterior ventral direction. Issues associated with the application of the investigated parameters for the purposes of mollusc species identification are discussed.

scholarly journals Quantification of mantle attachment scars on the Margaritifera margaritifera (Margaritiferidae, Bivalvia) shell

2019 ◽  
Vol 19 (2) ◽  
pp. 81-86
Author(s):  
A. A. Zotin ◽  
E. P. Ieshko
Keyword(s):  
Factor Analysis ◽  
Characteristic Feature ◽  
Species Identification ◽  
Internal Surface ◽  
Regression Coefficients ◽  
Margaritifera Margaritifera ◽  
Shell Surface ◽  
Significant Difference ◽  
Mollusc Species ◽  
Quantitative Indicators

A characteristic feature shared by all Margaritiferidae mussels consists in the presence of scars on the internal surface of their shells. These scars mark places of mantle attachment by specific epithelial cells. According to some authors, such parameters of mantle attachment scars as the density and degree of their manifestation can be used for the purposes of species identification. To this end, quality indicators (numerous or few, pronounced or poorly visible scars) are typically used; however, the use of quantitative criteria is preferable. This work was aimed at developing quantitative indicators of mantle attachment scars in the Margaritifera margaritifera freshwater pearl mussels for the populations of the Syuskyuyanyoki and Livoyoki rivers (Karelia). It is shown that the density and size of mantle attachment scars are approximately the same for all the investigated shell samples. These parameters display the absence of dependence on the age and size of molluscs. The regression coefficients for the linear dependence of the density or size of mantle attachment scars on the age or length of the shell show no significant difference from 0. For all the investigated molluscs, the density and size of mantle attachment scars are established to vary within the range of 0.37–1.16 scars/cm2 (0.71 ± 0.03 scars/cm2 on average) and 215–690 µm (417 ± 2 µm on average), respectively. According to a two-factor analysis of variance, the distribution of mantle attachment scars appears to be irregular across the shell surface. At the same time, a significant (p < 0.001) increase in their density is observed in the posterior and ventral directions, as well as diagonally in the posterior ventral direction. Issues associated with the application of the investigated parameters for the purposes of mollusc species identification are discussed.

Visual-based deep sea docking simulation of underwater vehicle using dual-eyes cameras with lighting adaptation

2016 ◽  
Author(s):  
Myo Myint ◽  
Kenta Yonemori ◽  
Akira Yanou ◽  
Khin Nwe Lwin ◽  
Mamoru Minami ◽  
...  
Keyword(s):  
Deep Sea ◽  
Docking Simulation ◽  
Underwater Vehicle

Application of the concept of criterion of a complex stress state to a simple tension for appraisal of resistance of fatigue of structural materials. Part 2. Drawing up criterion and its checking on compliance to experimental data

2021 ◽  
pp. 41-45
Author(s):  
P.N. Kozlov
Keyword(s):  
Experimental Data ◽  
Stress State ◽  
Structural Material ◽  
Complex Stress ◽  
Complex Stress State ◽  
Static Loads ◽  
Regular Change ◽  
Regular Cycle ◽  
Simple Tension ◽  
Dangerous Point

The criterion for appraisal of resistance of fatigue of structural material at action on it of repeatedly variables loads and static loads in the form of a bend or tensioncompression together with torsion, and also at action of loads, which create two-axis regular change of stress state in a dangerous point of material is constructed. The received criterion will acceptable be coordinated with the known experimental data. Keywords: dangerous point of material, regular cycle of loading, equivalent amplitude, equivalent average stress, chart of extreme amplitudes of stresses. [email protected]

Sign in / Sign up

Export Citation Format

Share Document