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When water damage occurs in a mine, variations in the immersion levels of tunnels at different burial depths can be observed. There is a significant relationship between the stability of the surrounding rock and the depth of immersion. Therefore, studying the deformation and damage characteristics of sandstone with circular holes at varying immersion depths, along with their acoustic properties, plays a crucial role in maintaining the stability of water-rich roadways. The TAW-2000 press and static strain system were utilized to investigate the mechanical properties, crack evolution, and deformation field distribution of sandstone with circular holes at varying immersion depths. Additionally, this study analyzed the impact of immersion depth on the characteristic parameters of acoustic emission. The results indicate that immersion depth is negatively correlated with the compressive strength and modulus of elasticity of sandstone; as immersion depth increases, the duration of the compression and yield phases of the rock samples also increases, while the duration of the elastic phase remains relatively unaffected. Furthermore, greater immersion depths correspond to a decrease in the total number of cracks, although the proportion of tensile cracks increases, making the formation of secondary cracks less likely. The frequency of acoustic emission events (transient elastic waves generated by the formation, extension, or closure of tiny cracks within the rock) shows a closely correlated dynamic with the stress–time curve of the rock sample. The acoustic emission ringing counts generated by rock samples under submerged water conditions tend to stabilize with a slight increase before signs of rupture appear. Additionally, the cumulative total energy of acoustic emissions from the rock samples decreases as the water level rises. These research findings provide significant reference value for addressing issues related to water immersion and the extent of water saturation in roadways within rock engineering. [ABSTRACT FROM AUTHOR]

Quantitative visualization experiments and numerical simulations on cylindrical "alien" particles penetrating a liquid-saturated granular bed have been performed. The bed consists of mono-sized spheres. In dimensionless terms the bed is characterized by an Archimedes number, an angle of repose that represents friction, and a solids volume fraction. The conditions are such that the fluid flow generated by alien and bed particle motion is laminar. The experiments are well reproducible. The most important experimental observation is deeper penetration of the alien particle for higher liquid viscosities. The spatial resolution of the three-dimensional, time-dependent simulations is such that they resolve the flow around, and the motion of the individual particles. The flow solver is based on the lattice-Boltzmann method. To a certain extent the simulations are able to reproduce the viscosity effect observed experimentally. [ABSTRACT FROM AUTHOR]

When water damage occurs in a mine, variations in the immersion levels of tunnels at different burial depths can be observed. There is a significant relationship between the stability of the surrounding rock and the depth of immersion. Therefore, studying the deformation and damage characteristics of sandstone with circular holes at varying immersion depths, along with their acoustic properties, plays a crucial role in maintaining the stability of water-rich roadways. The TAW-2000 press and static strain system were utilized to investigate the mechanical properties, crack evolution, and deformation field distribution of sandstone with circular holes at varying immersion depths. Additionally, this study analyzed the impact of immersion depth on the characteristic parameters of acoustic emission. The results indicate that immersion depth is negatively correlated with the compressive strength and modulus of elasticity of sandstone; as immersion depth increases, the duration of the compression and yield phases of the rock samples also increases, while the duration of the elastic phase remains relatively unaffected. Furthermore, greater immersion depths correspond to a decrease in the total number of cracks, although the proportion of tensile cracks increases, making the formation of secondary cracks less likely. The frequency of acoustic emission events (transient elastic waves generated by the formation, extension, or closure of tiny cracks within the rock) shows a closely correlated dynamic with the stress–time curve of the rock sample. The acoustic emission ringing counts generated by rock samples under submerged water conditions tend to stabilize with a slight increase before signs of rupture appear. Additionally, the cumulative total energy of acoustic emissions from the rock samples decreases as the water level rises. These research findings provide significant reference value for addressing issues related to water immersion and the extent of water saturation in roadways within rock engineering.

This paper is based on the surface defects of casting billets in the production process of nonoriented silicon steel plates at a steel plant in North China. Taking the parameters of a slab mold in the nonoriented silicon steel production process as a prototype, the flow field characteristics of the mold under the same section, different drawing speed and immersion depth were systematically studied by using a LES (large eddy simulation) and VOF (volume of fluid) coupling algorithm. The results show that under the current conditions, when the critical slag entrapment speed increases from 1.0 m/min to 1.2 m/min, the nozzle insertion depth increases linearly with the critical slag entrapment speed, while when the nozzle insertion depth exceeds 130 mm, the increasing effect of further increasing the nozzle insertion depth on the critical slag entrapment speed begins to decrease. When the drawing speed of continuous casting is kept constant at 1.4 m/min, the abnormal fluctuation height of the steel slag interface is significantly improved when the angle of the water nozzle is increased from 15° to 20°, and the proportion of slag entrapment is also reduced from 0.376% to 0.015%. When the nozzle angle is 25°, the slag entrapment ratio is reduced to 0%, and the steel slag interface also ensures a certain activity. The numerical simulation results were applied to the industrial site, and the slag inclusion rate and crack rate of the billet in the continuous casting process of nonoriented silicon steel were obviously improved after the optimization process. [ABSTRACT FROM AUTHOR]

Photovoltaic systems are one of the important methods used to obtain electricity from solar energy. Photovoltaic module temperature and the angle of incidence of solar radiation are the most important factors affecting the electrical energy obtained from the photovoltaic module. There are many experimental and numerical studies in the literature on increasing electricity production by cooling photovoltaic modules. Cooling with air, liquid, phase change materials, thermoelectric effect, and immersion in water are the commonly used cooling methods. In this study, the cooling of the photovoltaic module by the water immersion method was experimentally investigated. In addition to the results of the related studies in the literature, analyzes were made for different immersion depths and the most appropriate immersion depth was tried to be determined. Three scenarios, 5 cm, 20 cm, and 30 cm immersion depth were investigated in the immersion of the PV module in liquid. As a result of immersion of the PV module in water, the PV module temperature decreased, and the voltage output increased for all parameter values. The highest voltage increase was obtained for 5 cm immersion depth (7.85%). Although PV module temperatures decreased with increasing immersion depth, the voltage output decreased after 5 cm immersion depth.

This paper investigates the force features of inclined pipes under the action of waves and flows through both test and numerical simulation. Firstly, the wave and flow loads on inclined pipes were examined through tests in circulating water flumes. Next, the unsteady Reynolds-averaged Navier-Stokes (RANS) equations were adopted to numerically simulate the test conditions. Multiple factors were taken into consideration: immersion depth, inclination, flow rate, wave height, and cycle. The results show that, the wave and flow loads on the pipes both increase with wave height and flow rate. When the inclination β = 0°, the flow force is most rapid, conversely, it is most slow when the inclination β = 30°. Furthermore, when the pipe was immersed by 75%, the change of inclination directly affected the ratio of vertical force to horizontal force. For the pipes with different inclinations, the wave load increases basically at the same rate with the rising wave height. With the widening of the inclination, the wave and flow loads on the pipes become less sensitive to immersion depth, and the maximum loads remain near the free water surface.

• Vibroacoustic response of a submerged coated shell is presented • Uniform and locally resonant coatings with cavities or hard inclusions are considered • Coated shells partially or fully submerged close to a free surface are modelled • Coupled effect of coating designs and free surface on shell responses are described We study the vibroacoustic response of a coated cylindrical shell semi-immersed or fully submerged close to a free sea surface. Different coating designs corresponding to a uniform coating made of a viscoelastic material and locally resonant coatings composed of the viscoelastic material embedded with cavities or hard inclusions are considered. Analytical models that account for fully coupled fluid-structure interaction between the coated shell, the surrounding fluid domain and the free sea surface are developed. The free surface is treated as a pressure release boundary. For a fully submerged coated shell, the image method is employed. For the semi-immersed coated shell, a partial fluid loading condition is imposed on the wetted coating surface. The combined influence of the different coating designs and free surface on the structural and acoustic responses of the semi- and fully immersed shells are described. The influence of variation in dominant coating parameters that primarily impact the local resonances of the inclusions is also reported. [ABSTRACT FROM AUTHOR]

This paper investigates the force features of inclined pipes under the action of waves and flows through both test and numerical simulation. Firstly, the wave and flow loads on inclined pipes were examined through tests in circulating water flumes. Next, the unsteady Reynolds-averaged Navier-Stokes (RANS) equations were adopted to numerically simulate the test conditions. Multiple factors were taken into consideration: immersion depth, inclination, flow rate, wave height, and cycle. The results show that, the wave and flow loads on the pipes both increase with wave height and flow rate. When the inclination β = 0°, the flow force is most rapid, conversely, it is most slow when the inclination β = 30°. Furthermore, when the pipe was immersed by 75%, the change of inclination directly affected the ratio of vertical force to horizontal force. For the pipes with different inclinations, the wave load increases basically at the same rate with the rising wave height. With the widening of the inclination, the wave and flow loads on the pipes become less sensitive to immersion depth, and the maximum loads remain near the free water surface. [ABSTRACT FROM AUTHOR]

[Display omitted] We test whether the wettability of nanoparticles (NPs) straddling at an air/water surface or oil/water interface can be extrapolated from sessile drop-derived macroscopic contact angles (mCAs) on planar substrates, assuming that both the nanoparticles and the macroscopic substrates are chemically equivalent and feature the same electrokinetic potential. Pure silica (SiO 2) and amino-terminated silica (APTES-SiO 2) NPs are compared to macroscopic surfaces with extremely low roughness (root mean square [RMS] roughness ≤ 2 nm) or a roughness determined by a close-packed layer of NPs (RMS roughness ∼ 35 nm). Equivalence of the surface chemistry is assessed by comparing the electrokinetic potentials of the NPs via electrophoretic light scattering and of the macroscopic substrates via streaming current analysis. The wettability of the macroscopic substrates is obtained from advancing (ACAs) and receding contact angles (RCAs) and in situ synchrotron X-ray reflectivity (XRR) provided by the NP wettability at the liquid interfaces. Generally, the RCA on smooth surfaces provides a good estimate of NP wetting properties. However, mCAs alone cannot predict adsorption barriers that prevent NP segregation to the interface, as is the case with the pure SiO 2 nanoparticles. This strategy greatly facilitates assessing the wetting properties of NPs for applications such as emulsion formulation, flotation, or water remediation. [ABSTRACT FROM AUTHOR]

The article concerns the issue of improving the design and increasing the stability of a telescopic water intake. The design features and operation principles of the existing water intakes are analyzed and their disadvantages are revealed. The article proposes design solutions to improve and increase the stability of the telescopic water intake in the presence of external influences that contribute to the overturning and destruction of the device. In order to increase the stability of the telescopic water intake, a pile structure with a peculiar connection to the water intake float is proposed. A methodology for calculating and designing a telescopic water intake is described and a specific example for its implementation is given. [ABSTRACT FROM AUTHOR]

In this study, the moving particle semi-implicit (MPS) method is employed for numerical simulation of flow field in gearbox of high-speed railway trains so as to understand the lubrication mechanism and mode in the gearbox during high-speed operation. A high-fidelity 3D model for a high-speed train gearbox under actual working conditions is created for the first time. RecurDyn and ParticleWorks co-simulation is conducted to acquire the flow field distribution in the gearbox under the coupling of multi-fields and to calculate the churning losses. Effects of key parameters including rotation speed, viscosity, and immersion depth on the churning power losses of the gearbox are investigated to determine their influences on the lubrication performance of the gearbox. Those results form a theoretical base for futuristic optimization of the high-speed train gearboxes.

Membrane fouling is still the main obstacle that hinders the development and implementation of anaerobic membrane bioreactor (AnMBR). In conventional upflow anaerobic reactors, sludge at different height usually presents certain differences in characteristics in terms of particle size, etc. The immersion depth of membrane modules in anaerobic reactors can also influence the fouling of membrane. Thus, it is of great interest to investigate the fouling mechanism with the membrane installed at different heights in reactors. The filtration performance and sludge properties were investigated at different heights of AnMBR. The fouling of membrane in the middle position was severer than that in the top and bottom positions. The total resistance of membrane in the top, middle, and bottom positions was 27.31 × 1011 m−1, 34.67 × 1011 m−1, and 25.29 × 1011 m−1, respectively. By comparing the characteristics and structure of bulk sludge and cake layer at three heights, the bulk sludge in the middle position presented higher content of soluble microbial products (SMP) and finer flocs, and the cake layer was also denser. The results obtained in this study indicated that small size of sludge flocs as well as adhesion of SMP might be the major factors governing membrane fouling at different height in the AnMBR. [ABSTRACT FROM AUTHOR]

Application of microwave energy at 2.45 GHz frequency has the potential to provide thermal energy-based alternative solution to drilling of glass in the sub-millimeter domain. In this process, the concentrated microwave energy around a concentrator (tool) is utilized to melt or ablate the target material from the workpiece. The present study discusses the effect of parameters like tool shape, tool immersion depth, feed rate, and machining gap on the quality of hole in terms of thermal damage, overcut, and amount of material removed while drilling borosilicate glass using a graphite concentrator. It was found that the concentrator with a conical tip performs better compared to the concentrator with cylindrical tip due to concentration of thermal energy at the tip. Further, it was observed that the thermal damage, overcut, and amount of material removed decrease with the increase in immersion depth and feed rate. A machining gap (~ 300 μm) between the concentrator tip and the workpiece is essential as it facilitates flushing the glass residue from the machining zone. Effective flushing also reduces thermal damage and roundness error around the hole drilled. However, overcut and amount of material removed increases with increase in the machining gap due to increased plasma zone area and interaction time between plasma and the workpiece. The results of heat-affected zone obtained from this research were significantly less compared to that in published results. The approach was found to be promising while drilling borosilicate glass, though further study will be needed to improve precision. [ABSTRACT FROM AUTHOR]

In this study, the performance of the ultra-low head undershot fixed-blade and flip-blade waterwheels are studied via numerical simulations to evaluate their efficiency and stability. On the other hand, the accuracy of the numerical simulation of the fixed-blade waterwheel is verified by field tests before the flip-blade waterwheel is designed on its basis. Moreover, the likelihood of fish injury in the fixed-blade waterwheel is predicted to evaluate the fish-friendliness of the waterwheel. Applying the overset grid algorithm, the results indicate that the fish is most vulnerable to damage in the rotor area and that the fish suffer some impact damage but almost no pressure and shear stress damage, and a minimal probability of mortality present, confirming that the waterwheel is fish friendly. Furthermore, the power coefficient of the waterwheel with the rise of tip speed ratio tends to increase first and then decrease, while maintaining a positive correlation with the immersion depth within a certain range. Additionally, flip-blade owns higher efficiency than fixed-blade waterwheel under the same working conditions but is slightly less stable. We expect that these results will help establish design guidelines for more efficient flip-blade waterwheels to break the impression that traditional undershot waterwheels are less efficient. [ABSTRACT FROM AUTHOR]

The Kanbara Reactor (KR) is a primary desulfurization technology in the hot metal pretreatment refining process that is widely employed in the modern steelmaking industry. The operating parameters of KR impeller immersion depth (IID) and rotation speed (IRS) have a crucial impact on the process performance and the desulfurization effect. Still, their influences have not been fully understood. This study systematically investigated the effects of IID and IRS on the flow pattern, mixing behavior, vortex core depth, and free surface characteristics for KR processes based on a 3D Volume of Fluid (VOF) model coupled with the sliding mesh method (SMM). The model was validated via scale-down water model experiments and then applied to the KR process, and simulations found that IID and IRS have different impacts on the flow pattern. Specifically, the discharge flow location moves downward with IID increasing, but the discharge strength and mean velocity hardly changes. Comparatively, the rise of IRS significantly increases the mean velocity, but few changes occur to the discharge flow position. Increasing IRS improves bath hydrodynamics, strengthens recirculation, and efficiently shortens mixing time, but IID has a neglectable effect on these features. The minimum mixing time is 55 s at a maximum IRS of 260 rpm. Moreover, the vortex core depth and free surface velocity visibly increase with the increase of IRS. Comparatively, IID has a limited effect on the flow and mixing behavior but directly impacts the distribution of recirculation regions at the axial direction and the velocity gradient on the free surface at the radial direction. Furthermore, the correlation equations of these critical parameters as a function of the operating parameters were obtained. The results from this study may provide references for operating optimizations and industrial practices of KRs.

Aiming at the frequent lubrication accidents of the high-speed train gearbox,the theoretical calculation of required volume of the gearbox lubrication oil is carried out. The effective volume of gearbox lubrication oil on the specific immersion depth is also calculated by the Fluent. The flow field of the gearbox is optimized,and the effective volume of the gearbox lubrication oil is increased,and the factors affecting on the effective volume of the gearbox lubrication oil are determined. The theoretical calculation of the changing situation of stirring oil loss and the thermal equilibrium temperature of gearbox with the speed under different immersion depths is carried out. The analysis shows that the gearbox structure resistance reduced the effective volume of lubrication oil. The effective volume of lubrication oil and the churning losses of the gearbox increases with the immersion depth increases. The thermal balance temperature rises with the immersion depth increases or speed increases.

Copyright of Electrometallurgy Today / Sovremennaya Elektrometallurgiya is the property of International Association Welding (Paton Publishing House) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the electroslag remelting process, the electrode molten state is a critical factor determining the ingot quality, while the electrode immersion depth and melting rate are key factors for the stability of the electroslag re-melting process. Studies were carried out to investigate the microscopic and macroscopic effects of electrode immersion depth and melting rate on the potential distribution and heat density in the slag bath, and on the depth and shape of the molten bath. Based on the finite element method and the numerical solution method, the effect of the electrode immersion depth on the slag bath heat density was researched; the relationship between the electrode immersion depth and the slag resistance was obtained; and the unsteady-state model of the solidification process of the re-melting ingot was solved using the finite difference method. The mathematical model and physical model of the electrode melting process were established and solved; and the corresponding curves between the electrode molten-state and slag-bath physical parameters were obtained. The experimental results verified the simulated results studied in this paper.

Copyright of Scientific Journal of National University of Life & Environmental Sciences of Ukraine. Series: Technique & Energy of APK is the property of National University of Life & Environmental Sciences of Ukraine and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Research and design a 45 m³ mechanical flotation machine in order to achieve a large-scale, high efficiency, energy conservation flotation machine. Describe the structure and operating principle of the flotation machine, focus on the structural design of the tank impeller, stator, scraping bubble agencies, steady flow plates in the flotation machine. The performance test by water flotation machine show that, when the impeller speed is 137.58 m/s, immersion depth is 895 mm, the flotation machine has a optimal process indicators. The application of 45 m³ mechanical flotation machine in Dayangquan coal preparation plant shows that, the ash of clean coal is 10. 69%, the ash of tailings is 55.35%, the yield of clean coal is 68.03%.The flotation machine has good recovery effects on different size fractions slime. Compared with FCMC3000 flotation column, in the case of the feed ash has a little difference, the tailings ash, coal yield, combustible body recovery, improve index of the XJM-S45 flotation machine flotation increased by 18.61%, 18.84%, 23.90%, 18.30%. [ABSTRACT FROM AUTHOR]

Abstract: The reduction in EPR signal intensity of nitroxide spin-labels by ascorbic acid has been measured as a function of time to investigate the immersion depth of the spin-labeled M2δ AChR peptide incorporated into a bicelle system utilizing EPR spectroscopy. The corresponding decay curves of n-DSA (n=5, 7, 12, and 16) EPR signals have been used to (1) calibrate the depth of the bicelle membrane and (2) establish a calibration curve for measuring the depth of spin-labeled transmembrane peptides. The kinetic EPR data of CLS, n-DSA (n=5, 7, 12, and 16), and M2δ AChR peptide spin-labeled at Glu-1 and Ala-12 revealed excellent exponential and linear fits. For a model M2δ AChR peptide, the depth of immersion was calculated to be 5.8Å and 3Å for Glu-1, and 21.7Å and 19Å for Ala-12 in the gel-phase (298K) and Lα-phases (318K), respectively. The immersion depth values are consistent with the pitch of an α-helix and the structural model of M2δ AChR incorporated into the bicelle system is in a good agreement with previous studies. Therefore, this EPR time-resolved kinetic technique provides a new reliable method to determine the immersion depth of membrane-bound peptides, as well as, explore the structural characteristics of the M2δ AChR peptide. [Copyright &y& Elsevier]

Abstract: Based on the systematic study of electropolishing process, an improved tungsten STM probe fabrication technique has been presented. The proper combination of pulse current and the electrolyte concentration is explored for the elimination of impurities and achieves high quality probes with ultra-smooth surfaces. An optimized immersion depth of tungsten wire in electrolyte is proposed for the purpose of realizing the probe with sharp apex as well as high aspect ratio structure. A control strategy for determining the power-off instant during the procedure of electropolishing is developed which will facilitate the fabrication of probe with exponential contour as well as ultrasharp tip. The proposed technique and process are experimentally confirmed to have advantages for the STM probe fabrication of the stabilized stylus contour, typically with apex radius of 30nm and the yield rate reaches as high as 85%. [Copyright &y& Elsevier]

The effects of the free surface on the flow around a rotating propeller were investigated experimentally in a circulating water channel by varying the propeller immersion depth. Instantaneous velocity fields were measured using a two-frame particle image velocimetry (PIV) technique at four blade phases. These fields were ensemble averaged to obtain the phase-averaged flow structure of both the inflow and the wake. The flow around the propeller was influenced by the propeller rotation speed, the loading on the blades, and the proximity of the propeller to the free surface. The boundary layers developed on the blade surfaces led to the formation of viscous wake at all immersion depths. As the propeller was moved closer to the free surface, the axial velocity within the slipstream decreased. Interaction between the tip vortices and the slipstream seemed to cause the tip vortices to follow an oscillating trajectory. The presence of the free surface greatly affected the wake structure, especially for the propeller immersion depth of 0.6 D. At small immersion depths, the free surface modified the tip and trailing vortices and the slipstream flow structure downstream of X/D = 0.3 in the propeller wake. The present study shows that wake modeling should consider the free surface effects to accurately predict propeller performance or cavitation at small propeller immersion depths. [ABSTRACT FROM AUTHOR]

Investigations were made in back-to-back gear test rigs measuring the beneficial effects of a low oil immersion depth due to reduced drag and churning losses of the gears as well as the detrimental effects of increased gear bulk temperatures and increased gear failure risks. In these cases the oil amount required for lubrication may still be sufficient but oil cooling is often minimised. The influence of the gear immersion depth on scuffing performance of case carburised gears was determined in systematic investigations as a function of immersion depth, speed and direction of rotation. The results of the experimental investigations are presented and their introduction into calculation methods is discussed. [ABSTRACT FROM AUTHOR]

Abstract: An important component of the study of membrane proteins involves the determination of details associated with protein topology — for example, the location of transmembrane residues, specifics of immersion depth, orientation of the protein in the membrane, and extent of solvent exposure for each residue. Solution state NMR is well suited to the determination of immersion depth with the use of paramagnetic additives designed to give rise to depth-specific relaxation effects or chemical shift perturbations. Such additives include spin labels designed to be “anchored” within a given region of the membrane or small freely diffusing paramagnetic species, whose partitioning properties across the water membrane interface create a gradient of paramagnetic effects which correlate with depth. This review highlights the use of oxygen and other small paramagnetic additives in studies of immersion depth and topology of membrane proteins in lipid bilayers and micelles. [Copyright &y& Elsevier]

The Kanbara Reactor (KR) is a primary desulfurization technology in the hot metal pretreatment refining process that is widely employed in the modern steelmaking industry. The operating parameters of KR impeller immersion depth (IID) and rotation speed (IRS) have a crucial impact on the process performance and the desulfurization effect. Still, their influences have not been fully understood. This study systematically investigated the effects of IID and IRS on the flow pattern, mixing behavior, vortex core depth, and free surface characteristics for KR processes based on a 3D Volume of Fluid (VOF) model coupled with the sliding mesh method (SMM). The model was validated via scale-down water model experiments and then applied to the KR process, and simulations found that IID and IRS have different impacts on the flow pattern. Specifically, the discharge flow location moves downward with IID increasing, but the discharge strength and mean velocity hardly changes. Comparatively, the rise of IRS significantly increases the mean velocity, but few changes occur to the discharge flow position. Increasing IRS improves bath hydrodynamics, strengthens recirculation, and efficiently shortens mixing time, but IID has a neglectable effect on these features. The minimum mixing time is 55 s at a maximum IRS of 260 rpm. Moreover, the vortex core depth and free surface velocity visibly increase with the increase of IRS. Comparatively, IID has a limited effect on the flow and mixing behavior but directly impacts the distribution of recirculation regions at the axial direction and the velocity gradient on the free surface at the radial direction. Furthermore, the correlation equations of these critical parameters as a function of the operating parameters were obtained. The results from this study may provide references for operating optimizations and industrial practices of KRs. [ABSTRACT FROM AUTHOR]

• The hydrodynamics of a tunnel-rig system in random waves is experimentally studied. • Fully coupled mechanism of the system for different immersion depths is analyzed. • Relationship between the relative motion and the suspension tension is identified. An experimental investigation on the coupled dynamics of an offshore tunnel-rig system from the element launching to its near-seabed immersion in irregular waves is conducted, where the motions of tunnel/rigs and the tensile forces of the suspension lines are evaluated in a synchronous manner for a wide range of irregular waves. The effect of immersion depth on the coupled dynamics of the tunnel-rigs system, especially the relationship between the relative motion and suspension line tensions are experimentally examined. The system coupling mechanism is further addressed using the modal analysis and response spectra analysis. The results show that the natural frequencies of the coupled system are primarily affected by the varying immersion depth. The increasing immersion depth leads to a larger in-phase roll period of the system and a greater roll resonance amplitude. For a given immersion depth, a strong dependence of the suspension line tensions upon the relative motions is established. [ABSTRACT FROM AUTHOR]