Varying Aspect Ratio Research Articles

Utilization of cross‐correlation function for assessment of replication quality in ultrasonic embossing of microchannels on polymethyl methacrylate

AbstractUltrasonic embossing—a process where a horn vibrating at 20–30 kHz compresses on a thermoplastic substrate sitting on a mold to replicate the features on the mold to the substrate—is a promising method for fabricating microchannels on thermoplastics due to reduced cycle time and relatively low equipment cost. Replication quality in ultrasonic embossing has been investigated in the literature by primarily referring to the replication depth. However, this approach does not fully reflect the fidelity between the mold and the replicated feature, especially at the side walls, which are typically designed to be vertical in microchannels. We propose using cross‐correlation—a method that quantifies the similarity between two signals by measuring the overlap of their patterns—between the derivative of the mold profile and the embossed profile as a figure of merit that accurately reflects the fidelity of the side wall. For testing purposes, we embossed straight microchannels on polymethyl methacrylate (PMMA) using micron‐scaled protrusions on a brass mold fabricated by CNC milling. The mold comprised 100, 300, and 1000‐μm‐wide protrusions of same designed height of 300 μm, resulting in aspect ratios (AR) of 3, 1, and 1/3, respectively. Cross‐correlations between the derivatives of the profiles ranged between 0.50 and 1.00, while cross‐correlations between the profiles were greater than 0.97 in all cases, showing the sensitivity imposed by utilizing the derivatives. Setting average of all cross‐correlation values (0.8) as the quality threshold, we observed that high AR (3) features were replicated at low quality, while low AR (1/3) features were replicated at high quality, regardless of the process parameters. In replicating unit AR features, the process parameters were observed to affect the quality, where the combination of vibration time and pressure was the most significant compared to individual effects of the parameters.Highlights Parameters' effect on replication of varied aspect ratio features was assessed. Assessment was carried out by cross‐correlating mold and channel profiles. Cross‐correlating derivatives of profiles provide a more sensitive means. General rules for replication quality in ultrasonic embossing were driven.

Classification of complex local environments in systems of particle shapes through shape symmetry-encoded data augmentation.

Detecting and analyzing the local environment is crucial for investigating the dynamical processes of crystal nucleation and shape colloidal particle self-assembly. Recent developments in machine learning provide a promising avenue for better order parameters in complex systems that are challenging to study using traditional approaches. However, the application of machine learning to self-assembly on systems of particle shapes is still underexplored. To address this gap, we propose a simple, physics-agnostic, yet powerful approach that involves training a multilayer perceptron (MLP) as a local environment classifier for systems of particle shapes, using input features such as particle distances and orientations. Our MLP classifier is trained in a supervised manner with a shape symmetry-encoded data augmentation technique without the need for any conventional roto-translations invariant symmetry functions. We evaluate the performance of our classifiers on four different scenarios involving self-assembly of cubic structures, two-dimensional and three-dimensional patchy particle shape systems, hexagonal bipyramids with varying aspect ratios, and truncated shapes with different degrees of truncation. The proposed training process and data augmentation technique are both straightforward and flexible, enabling easy application of the classifier to other processes involving particle orientations. Our work thus presents a valuable tool for investigating self-assembly processes on systems of particle shapes, with potential applications in structure identification of any particle-based or molecular system where orientations can be defined.

Investigating urban canyons, façade albedo, and pedestrian thermal comfort using microclimate model calculations

Previous studies have shown a strong relationship between heat-related fatalities and ambient air temperature. This problem is expected to increase due to constant urbanization and the threat of global warming. Therefore, designing urban street canyons (USC) to be thermally comfortable is essential for a healthy urban life. This paper investigates the correlation between an urban street canyon’s aspect ratio and the albedo material of its surrounding buildings. The aim is to study which combination can successfully mitigate urban heat stress and create a thermally comfortable pedestrian microclimate. This research uses a comparative analysis that suggests the optimum albedo for different USC geometries. An ENVI-met model was used to simulate 9 scenarios for an idealized 2D USC with varying aspect ratios and albedo values. Air temperature, mean radiant temperature and Universal Thermal Climate Index (UTCI) were analyzed. Results show that a medium albedo value performs best thermally in all USCs. High albedo had 13.2% more combined thermal stress compared to medium albedo. However, high albedo performed much better in deep canyons than wider ones, with the average UTCI decreasing by about 4.8%-5.7% when used in deep canyons. Medium albedo should be exclusively used in wide canyons for minimal thermal stress. Practical application: This study provides a reference to the use of materials in urban street canyons of different aspect ratios to achieve good outdoor thermal comfort for pedestrians.

Thermal response of DNAN based explosives considering thermodynamic coupling：Under different charge quantity and diameter changes

This paper explores the impact of changes in charge quantity and diameter on the thermal response of DNAN-based explosives. To achieve this, we established a method for simulating thermal, chemical, and mechanical coupling. The study focuses on three fixed charge quantities of explosives, each with varying length-to-diameter ratios, examining alterations in ignition position, timing, and temperature changes under different heating rates, as well as the safe thermal response size in various heating environments. The findings show that the maximum discrepancy between the simulation results and experimental data is under 5 %. It was observed that larger charges are less sensitive to variations in external heating rates and aspect ratios. Specifically, at a heating rate of 1 K/min, projectiles with a diameter exceeding their length by the same factor exhibit greater thermal safety than those with a length exceeding their diameter. This research not only enhances the accuracy of simulation experiments but also offers a comprehensive safety analysis for the combustion of ammunition. The findings provide valuable insights for designing low-vulnerability ammunition structures that are subject to significant thermal stress in various environments, and they are useful for guiding ammunition storage and destruction experiments.

Hydrodynamic force and torque models for cylindrical particles in a wide range of aspect ratios

During the pneumatic conveyance of biomass in a coal-fired power station boiler, biomass particles have cylindrical shapes with different aspect ratios. They move through the fluid at any angle and rotate strongly. However, highly accurate and general models of the drag, lift, and torque coefficients (CD, CL, and CT) for biomass particles in a wide range of aspect ratios, especially the CT model and the high aspect ratios, are currently lacking. This paper presents detailed direct numerical simulations of the flow around cylindrical cylinders with varying aspect ratios (6 ≤ AR ≤ 22), Reynolds numbers (100 ≤ Re ≤ 2000), and angles of incidence (0° ≤ θ ≤ 90°). The simulation was conducted using the OpenFOAM solver with the body-fitted mesh method. The flow characteristics and force coefficients of cylindrical particles with different AR were systematically analyzed. New functional correlations between CD, CL, and CT and AR, Re, and θ values were established. The mean squared errors for CD, CL, and CT were 8.8 × 10–2, 2.4 × 10–2, and 4.7 × 10–2, with average relative errors of 5.8%, 3.5%, and 8.17%, respectively. A comparison of the results with other experimental and simulation data in previous literatures showed that the new CD and CL models have considerable higher predictive ability. The generality of the new CD model expanding to low ARs of 1.5 and 3 is verified finally. The new force and torque models are expected to improve the accuracy of Eulerian–Lagrangian simulations of various cylindrical particle-laden flows in the utility of biomass energy.

Gas–solid flow mechanism of spherocylindrical particles with various aspect ratios in spouted bed

Spherocylindrical particles encompass elongated spherical particles, such as biomass particles utilized in thermal reactions and capsule pills in the pharmaceutical industry, along with various other particles found in industrial production processes. Understanding the flow behavior of spherocylindrical particles within a spouted bed holds significant practical importance. This study delves into investigating the fluidization characteristics of spherocylindrical particles with varying aspect ratios within a spouted bed. Key parameters studied include particle void fraction, velocity, orientation, and mixing. These were analyzed using the computational fluid dynamics–discrete element method, and the simulation model's accuracy was verified through high-speed photography experiments. The findings revealed distinct void fraction distributions at different locations within the bed. Particles in the higher-bed region exhibited larger void fractions with flatter peaks compared to those in the lower-bed region. Moreover, the correlation between particle aspect ratio and void fraction varied at different heights within the bed. Notably, there was no significant correlation observed between particle aspect ratio and particle velocity. However, the larger the particle aspect ratio/gas velocity, the better the particle mixing quality. Additionally, gas velocity and particle aspect ratio had little effect on particle orientation, but there was a tendency for particle orientation angles to hover around 45°–60° near the wall region.

Regional shear wave speeds track regional axial stress in nonuniformly loaded fibrous soft tissues

Ligaments and tendons undergo nonuniform deformation during movement. While deformations can be imaged, it remains challenging to use such information to infer regional tissue loading. Shear wave tensiometry is a promising noninvasive technique to gauge axial stress and is premised on a tensioned beam model. However, it is unknown whether tensiometry can predict regional stress in a nonuniformly loaded structure. The objectives of this study were to (1) determine whether regional shear wave speed tracks regional axial stress in nonuniformly loaded fibrous soft tissues, and (2) determine the sensitivity of regional axial stress and shear wave speed to nonuniform load distribution and fiber alignment. We created a representative set of 12,000 dynamic finite element models of a fibrous soft tissue with probabilistic variations in fiber alignment, stiffness, and aspect ratio. In each model, we applied a randomly selected nonuniform load distribution, and then excited a shear wave and tracked its regional propagation. We found that regional shear wave speed was an excellent predictor of the regional axial stress (RMSE = 0.57 MPa) and that the nature of the regional shear wave speed-stress relationship was consistent with a tensioned beam model (R2 = 0.99). Variations in nonuniform load distribution and fiber alignment did not substantially alter the wave speed-stress relationship, particularly at higher loads. Thus, these findings suggests that shear wave tensiometry could provide a quantitative estimate of regional tissue stress in ligaments and tendons.

Fine-Tuning of the Excitonic Response in Monolayer WS2 Domes via Coupled Pressure and Strain Variation.

We present a spectroscopic investigation of the vibrational and optoelectronic properties of WS2 domes in the 0-0.65 GPa range. The pressure evolution of the system morphology, deduced by the combined analysis of Raman and photoluminescence spectra, revealed a significant variation in the dome's aspect ratio. The modification of the dome shape caused major changes in the mechanical properties of the system resulting in a sizable increase of the out-of-plane compressive strain while keeping the in-plane tensile strain unchanged. The variation of the strain gradients drives a nonlinear behavior in both the exciton energy and radiative recombination intensity, interpreted as the consequence of a hybridization mechanism between the electronic states of two distinct minima in the conduction band. Our results indicate that pressure and strain can be efficiently combined in low dimensional systems with unconventional morphology to obtain modulations of the electronic band structure not achievable in planar crystals.

Simulation of Starch Gel Printing and Deformation Process Using COMSOL.

The food industry holds immense promise for 3D printing technology. Current research focuses mainly on optimizing food material composition, molding characteristics, and printing parameters. However, there is a notable lack of comprehensive studies on the shape changes of food products, especially in modeling and simulating deformations. This study addresses this gap by conducting a detailed simulation of the starch gel printing and deformation process using COMSOL Multiphysics 6.2 software. Additive manufacturing (AM) technology is widely acclaimed for its user-friendly operation and cost-effectiveness. The 3D printing process may lead to changes in part dimensions and mechanical properties, attributable to the accumulation of residual stresses. Studies require a significant amount of time and effort to discover the optimal composition of the printed material and the most effective deformed 3D structure. There is a risk of failure, which can lead to wasted resources and research delays. To tackle this issue, this study thoroughly analyzes the physical properties of the gel material through COMSOL Multiphysics 6.2 software, It simulates the heat distribution during the 3D printing process, providing important insights into how materials melt and solidify. Three-part models with varying aspect ratios were meticulously designed to explore shape changes during both the printing process and exposure to an 80 °C environment, employing NMR and rheological characterization. Using the generalized Maxwell model for material simulation in COMSOL Multiphysics, the study predicted stress and deformation of the parts by analyzing solid heat transfer and solid mechanics physical fields. Simulation results showed that among three models utilizing a gel-PET plastic membrane bilayer structure, Model No. 1, with the largest aspect ratio, exhibited the most favorable deformation under an 80 °C baking environment. It displayed uniform bending in the transverse direction without significant excess warpage in the edge direction. In contrast, Models No. 2 and No. 3 showed varying degrees of excess warpage at the edges, with Model No. 3 exhibiting a more pronounced warpage. These findings closely aligned with the actual printing outcomes.

Colloidal phase behavior of high aspect ratio clay nanotubes in symmetric and asymmetric electrolytes

HypothesisImogolite nanotubes (INTs) are unique anisometric particles with monodisperse nanometric diameters. Aluminogermanate double-walled INTs (Ge-DWINTs) are obtained with variable aspect ratios by controlling the synthesis conditions. It thus appears as an interesting model system to investigate how aspect ratio and ionic valence influence the colloidal behavior of highly anisometric rods. ExperimentsThe nanotubes were synthesized by hydrothermal treatment for 5 or 20 days to modify the aspect ratio while the electrostatic interactions were investigated by comparing the colloidal stability in symmetric and asymmetric electrolytes. The phase behavior and their related microstructure were determined by optical observations and small-angle X-ray scattering measurements, coupled with interparticle distance modelling. FindingsWe revealed that colloidal suspensions of Ge-DWINTs prepared in NaCl are guided by repulsive double layer forces, undergoing different liquid crystal phase transitions before stiffen into a glass-like state. We found that the microstructure can be rationalized by taking into account the anisometric nature of the particles. By contrast, dispersions prepared with asymmetric electrolytes are governed by strong attractive forces and thus form space-filling gels containing large nanotubes aggregates.

Tree form characteristics as criteria for tree species selection to improve pedestrian thermal comfort in street canyons: Case study of a humid subtropical city

The combined effect of tree characteristics on heat stress in different street canyons has been widely reported. However, there remains a lack of effective methods for improving pedestrian thermal comfort through the use of integrated knowledge of tree characteristics. Here, a tree species selection approach was developed for assessing the dynamic effects of tree forms and canyon geometries on pedestrian thermal comfort to address the issue of the right tree in the right street canyon. The leaf area density (LAD), crown diameter (CD), tree height (HT), and trunk height (TH) were used as criteria for determining tree species characteristics, and the weighted outdoor thermal comfort autonomy (OTCAw) was adopted as a quantitative index of thermal comfort variation over time. In a case study of Wuhan, China, we evaluated the thermal comfort enhancement potential of 45 tree forms in street canyons with varying aspect ratios and orientations from 7:00 to 21:00 by using a validated ENVI-met model. Accordingly, tree pruning strategies and 19 optimal tree forms were proposed for corresponding street canyons. Our study provides insight into the optimal street tree species for minimizing heat exposure of pedestrians under various urban canyon configurations.

Thermal nanoconversion of ferromagnetic nanoislands

In this work, we investigate the use of post-fabrication thermal nanoconversion (TNC), using a heated scanning probe tip, to modify the magnetic properties of Ni80Fe20 elliptical nanoislands with varying aspect ratio. Despite Ni80Fe20 being unoptimized for TNC, by comparing quasistatic and dynamic magneto-optical Kerr effect microscopy measurements, we demonstrate that TNC at a contact temperature of 250 °C increases the saturation magnetization of the treated nanoislands, reaching a value close to 800 kA/m. Micromagnetic simulations of the nanoislands indicate that the TNC technique can be used to alter the remanent state, from a single domain to a vortex. These results demonstrate the opportunities afforded by TNC to modify the properties of selected areas in a thin film or a patterned sample, particularly when designing magnonic crystals and other nanomagnetic devices.

Controlled growth-dependent electrochemical behavior of cobalt and 1,3,5 benzene-tricarboxylic acid-based MOFs for efficient supercapacitor applications

This study investigates the synthesis and electrochemical performance of cobalt-BTC acid-based metal-organic frameworks (Co-MOFs) under different hydrothermal conditions. The crystal growth was controlled by varying the concentration of NaOH during synthesis, resulting in three Co-BTC MOF varieties (labeled as COMOFDW-0mM, COMOFDW-3mM, and COMOFDW-6mM). Exhaustive structural-microstructural characterizations, including X-ray diffraction (XRD), scanning electron microscopy (SEM), and N2 adsorption-desorption isotherms, elucidate the structural and morphological variation among these Co-BTC MOF varieties. The crystal structures of COMOFDW-0mM and COMOFDW-3mM exhibit similar laminar configurations, while COMOFDW-6mM shows major variations, such as changes in the coordination modes between BTC and cobalt complexes and differences in BTC plane directions in MOF crystal faces. SEM images reveal distinctive needle-like morphologies, and the as-synthesized crystals exhibit varying aspect ratios. Nitrogen adsorption-desorption isotherms indicate variations in the presence of micropores and mesoporosities, revealing microstructural differences. Electrochemical evaluations in a three-electrode system reveal superior performance for COMOFDW-6mM, with a maximum specific capacitance of 261.27 F/g, an energy density of 7.34 Wh/kg, and a maximum power density of 1325.2 W/kg under 2 M KOH electrolyte. Two-electrode coin cell measurements further validate its potential, maintaining competitive capacitance values. This systematic exploration of Co-MOFs not only elucidates the impact of growth conditions on crystal structures but also underscores the potential for tailoring electrochemical properties. Moreover, the findings present opportunities for further enhancements through composite strategies, opening new avenues for advancing MOFs in energy storage applications.

Domain Adaptation of Anchor-Free object detection for urban traffic

Modern detectors are mostly trained under single and limited conditions. However, object detection faces various complex and open situations in autonomous driving, especially in urban street scenes with dense objects and complex backgrounds. Due to the shift in data distribution, modern detectors cannot perform well in actual urban environments. Using domain adaptation to improve detection performance is one of the key methods to extend object detection from limited situations to open situations. To this end, this article proposes a Domain Adaptation of Anchor-Free object detection (DAAF) for urban traffic. DAAF is a cross-domain object detection method that performs feature alignment including two aspects. On the one hand, we designed a fully convolutional adversarial training method for global feature alignment at the image level. Meanwhile, images can generally be decomposed into structural information and texture information. In urban street scenes, the structural information of images is generally similar. The main difference between the source domain and the target domain is texture information. Therefore, during global feature alignment, this paper proposes a method called texture information limitation (TIL). On the other hand, in order to solve the problem of variable aspect ratios of objects in urban street scenes, this article uses an anchor-free detector as the baseline detector. Since the anchor-free object detector can obtain neither explicit nor implicit instance-level features, we adopt Pixel-Level Adaptation (PLA) to align local features instead of instance-level alignment for local features. The size of the object has the greatest impact on the final detection effect, and the object scale in urban scenes is relatively rich. Guided by the differentiation of attention mechanisms, a multi-level adversarial network is designed to perform feature alignment of the output space at different feature levels called Scale Information Limitation (SIL). We conducted cross-domain detection experiments by using various urban streetscape autonomous driving object detection datasets, including adverse weather conditions, synthetic data to real data, and cross-camera adaptation. The experimental results indicate that the method proposed in this article is effective.

Integrating artificial intelligence in investigating magneto-bioconvection flow of oxytactic microorganisms and nano-enhanced phase change material in H-type cavity

Nano-enhanced phase change materials is an effective way to improve the thermal characteristics and to minimize energy consumption. The bioconvection flow of nano-enhanced phase change materials is gaining more attention in recent investigations due to its significant applications in engineering and medical sciences. The present study aims to numerically explore magneto-bioconvection flow of nano-enhanced phase change materials in H-type cavity including oxytactic microorganisms. The cavity is constantly heated from the left and a right wall is maintained at cold temperature. The major focus of the current investigation is analyzing the flow and thermal features of the suspension of nano-enhanced phase change materials and a host fluid. The governing system is reduced to the dimensionless form by applying the appropriate transformation. Impact of pertinent parameters, porosity, cavity aspect ratio, Darcy, Hartmann, Lewis, Rayleigh, bioconvection Rayleigh numbers, radiation parameter, and Péclet number on bioconvection flow of oxytactic microorganisms in H-type cavity has been analyzed. Six various artificial neural network models are explored in order to estimate critical parameters with an artificial intelligence approach. It is found that the variations of a cavity aspect ratio are enhancing the bioconvection flow and phase change material. Increasing Hartmann number reduces the nanofluid velocity and distributions of oxygen and microorganisms. The Rayleigh and bioconvection Rayleigh numbers are playing an importance role in enhancing bioconvection flow and varying phase change material.As Ha increases from 10 to 100, at γ=900, there is a 1.67% decrease in the values of Nuavg and a 0.247% increase in Shavg. Among the study findings, the developed artificial neural networks can predict each parameter with high accuracy.

Thermal performance analysis of a novel Conical-Cylindrical-Conical cavity receiver for a Scheffler concentrated solar system

The thermal efficiency of a receiver is a critical component of the point focusing concentrated solar system, significantly impacting the overall system efficiency. A thermal performance analysis of the developed novel Conical-Cylindrical-Conical cavity receiver is carried out for the enhancement of its efficiency. The analysis involves varying aspect ratios (0.8, 1, and 1.2) of the receiver utilizing Computational Fluid Dynamics with ANSYS (Fluent 2023R1) and the discrete ordinates modeling technique. The simulation results reveal a peak thermal efficiency of 80.9 % for the receiver at mass flow rate of 0.035 kg/s. The experimental validation is performed using a 16 m2 concentrator solar Scheffler dish under real outdoor conditions in a hilly terrain of India. The average percentage error between the experimental results and the Computational Fluid Dynamics model simulation, is found to be 0.52 %.The results of study highlights the significant impact of design and aspect ratio on the thermal efficiency of the cavity receiver. This study is the first investigation into the aspect ratio of the novel Conical-Cylindrical-Conical cavity receiver for point focusing concentrated solar system, providing valuable insights for further research and industrial applications worldwide.

Steady flow of non-Newtonian fluids: Momentum and heat transfer around a rectangular cylinder

This research aims to explore the impact of cross-sectional aspect ratio (AR), power-law index (n), Reynolds number (Re), and Prandtl number (Pr) on convective heat transfer rates using the Nusselt number (Nu) and coefficient of drag (CD) as a key metric. Numerical simulations employ the ANSYS FLUENT solver with the finite volume method. The SIMPLE scheme couples pressure and velocity, and the QUICK differencing scheme discretizes convective terms. This study varies the aspect ratio by adjusting the length-to-width ratio (b/D) to explore different configurations of AR = 1–5 and Pr = 0.7, 1, and 7, which investigate 5 ≤ Re ≤ 10 and 0.2 ≤ n ≤ 1, respectively. An increase in the Reynolds number is observed to diminish the thermal boundary layer thickness, resulting in an escalation of heat transfer rates. Additionally, the Nusselt number exhibits an upward trend with an increase in the Prandtl number. The investigation reveals a decrease in Nu with an increase in both AR and n. Specifically, higher aspect ratios and power-law indices are associated with reduced heat transfer rates. The AR emerges as a significant factor, influencing the coefficient of drag, with CD values showing an increase as AR rises, particularly at low Re. Moreover, CD is found to increase with an elevation in the n value. This study explores new ground by investigating power-law fluid behavior and heat transfer phenomenon across varied aspect ratios. These insights not only enhance the design of heat transfer systems with non-Newtonian fluids but also pave the way for future research in this less explored domain.

Effect of Aluminium Fiber on the Strength property of Concrete

This experimental work is aimed at determining the influence of aluminium waste fiber on plain cement concrete. To achieve this aim, compressive strength test has been conducted. The compressive strength test has been conducted in Compression machine. The plain cement concrete with the ratio 1:1.5:3 at 0.55 water cement ratio has been utilized in this study. Aluminium waste has been used as additional material in concrete. The weight of aluminium has been taken from 0.5%, 1.5% and 1.5% by weight of cement of varying aspect ratios that are 2.5 (length=0.5 inch, width=5mm), 5 (length=1inch, width=5mm) and 7.5 (1.5 inch, 0.5mm). A total number of ten batches, each batch contained six cubes and were casted for evaluation of compressive strength test. The curing ages selected for this particular study have been 7 and 28 days. It has been observed in this study that aluminium waste has resulted into a decrease in compressive strength of concrete as compared to normal concrete. This study has made application of solid waste as addition material in concrete. Therefore, this study will be helpful to reduce environmental pollution.

Scaling ice-induced vibrations by combining replica modeling and preservation of kinematics

A modeling approach to simulate ice-induced vibrations of vertically sided offshore structures in ice tank experiments is presented. The technique combines replica modeling with the preservation of kinematics during ice-structure interaction. The technique was chosen based on the theoretical understanding that ice-induced vibrations are caused by an energy exchange between the structure and the ice. The mechanism is controlled by primarily four aspects: the kinematics during ice-structure interaction, the degree to which the ice can resist higher loading at low velocities prior to failure (velocity effect), the existence of a transition speed from ductile-to-brittle failure, and the mean ice load level.A model ice type which resulted in a velocity effect and provided a transition speed comparable to that of sea ice was developed and used during ice tank experiments. A scaling factor, derived from the comparison between the mean brittle crushing ice load of the full-scale event and the in-situ measured mean brittle crushing model ice load, was applied to scale structure properties of a numerical model. This model was implemented during real-time hybrid simulations in model ice to preserve kinematics during the ice-structure interaction.To verify the proposed scaling approach, rigid indenter experiments covering velocities from 0.1 mm s−1 to 500 mm s−1 and dynamic ice-induced vibration experiments of structures with varying aspect ratios (8 and 12) and shapes (cylindrical and rectangular) were conducted. Neither the aspect ratio nor shape appeared to influence the development of ice-induced vibrations significantly.The approach was qualitatively validated by reproducing full-scale ice-induced vibrations as experienced by the Molikpaq platform and Norströmsgrund lighthouse.

Influence of small inertia on Jeffery orbits

We experimentally investigate the rotational dynamics of neutrally buoyant axisymmetric particles in a simple shear flow. A custom-built shearing cell and a multi-view shape-reconstruction method are used to obtain direct measurements of the orientation and period of rotation of particles having oblate and prolate shapes (such as spheroids and cylinders) of varying aspect ratios. By systematically changing the viscosity of the fluid, we examine the effect of inertia (which may be originated from either phase) on the dynamical behaviour of these suspended particles up to a particle Reynolds number of approximately one. While no significant effect on the period of rotation is found in this small-inertia regime, a systematic drift among several rotations toward limiting stable orbits is observed. Prolate particles are seen to drift towards the tumbling orbit in the plane of shear, whereas oblate particles are driven either to the tumbling or to the vorticity-aligned spinning orbits, depending on their initial orientation. These results are compared with recent small-inertia asymptotic theories, assessing their range of validity, as well as to numerical simulations in the small-inertia regime for both prolate and oblate particles.