Variation Of Tension Research Articles

Modeling of interfacial area for single deformed bubble based on VOF method

Bubble geometric shape and hydrodynamic behavior affect directly mass, momentum and heat transfer at the interfacial area in the bubbly flow regime. A numerical model is developed to calculate instantaneous bubble interfacial area based on the VOF method. After data fitting, a new correlation is developed to associate the normalized bubble interfacial area with Eötvös and Galilei numbers. Considering the variation in liquid viscosity and surface tension of different gas–liquid systems, the influence of interface sharpening schemes on bubble hydrodynamics is illustrated comprehensively. With a moving reference frame, long-term bubble behavior is investigated in the air–water system and the temporal evolution of bubble hydrodynamics is analyzed in detail. Simulation results are validated by experimental data in terms of bubble rising velocity, aspect ratio and bubble deformation factor. The results indicated that the interface sharpening scheme affects the calculation of bubble interfacial area significantly. Both liquid viscosity and surface tension contribute to the formation of a stable terminal bubble interface. In the given range, the evolution of terminal interfacial area is found to agree well with the predicted correlation. Regarding long-term bubble behavior, three stages for instantaneous rising velocity and bubble interfacial area are observed, which are the damped oscillatory stage, the transition stage and the quasi-stable stage. Bubble deflection direction may be opposite to internal gas jet direction due to vortex shedding. In general, the numerical models applied in this study are proven to be feasible for bubble interfacial area calculation.

An Innovative Spiral Pulley that Optimizes Cable Tension Variation for Superior Balancing Performance

In modern manufacturing, the long-term handling of heavy objects is a main factor leading to muscle pain in the waist and lower back. Robots play an important role in reducing the burden on workers by compensating for the gravitational force. Energy-conserving passive mechanisms are commonly used in assistive robots because of their reliability and durability. One such mechanism is a spiral pulley and spring couple, which is a compact and reliable solution to provide a constant assistive force. A spiral pulley has a predesigned changing radius to balance the increasing restoring force of the spring as it extends. This allows the mechanism to exert a constant torque within the designed range. A crucial aspect of such a mechanism is the calculation of the shape of the spiral pulley. Accurate calculations enable the mechanism to provide a more optimal balancing ability. In this study, an innovative spiral pulley was designed by considering the cable tension variation along the cable attached to the pulley. The balancing performance of the proposed pulley was evaluated based on its accuracy in providing a balanced torque and an effective range. A comparative experiment using a conventional spiral pulley confirmed the effectiveness of the proposed pulley.

Architecture of the linker-scaffold in the nuclear pore.

INTRODUCTION In eukaryotic cells, the selective bidirectional transport of macromolecules between the nucleus and cytoplasm occurs through the nuclear pore complex (NPC). Embedded in nuclear envelope pores, the ~110-MDa human NPC is an ~1200-Å-wide and ~750-Å-tall assembly of ~1000 proteins, collectively termed nucleoporins. Because of the NPC's eightfold rotational symmetry along the nucleocytoplasmic axis, each of the ~34 different nucleoporins occurs in multiples of eight. Architecturally, the NPC's symmetric core is composed of an inner ring encircling the central transport channel and two outer rings anchored on both sides of the nuclear envelope. Because of its central role in the flow of genetic information from DNA to RNA to protein, the NPC is commonly targeted in viral infections and its nucleoporin constituents are associated with a plethora of diseases. RATIONALE Although the arrangement of most scaffold nucleoporins in the NPC's symmetric core was determined by quantitative docking of crystal structures into cryo-electron tomographic (cryo-ET) maps of intact NPCs, the topology and molecular details of their cohesion by multivalent linker nucleoporins have remained elusive. Recently, in situ cryo-ET reconstructions of NPCs from various species have indicated that the NPC's inner ring is capable of reversible constriction and dilation in response to variations in nuclear envelope membrane tension, thereby modulating the diameter of the central transport channel by ~200 Å. We combined biochemical reconstitution, high-resolution crystal and single-particle cryo-electron microscopy (cryo-EM) structure determination, docking into cryo-ET maps, and physiological validation to elucidate the molecular architecture of the linker-scaffold interaction network that not only is essential for the NPC's integrity but also confers the plasticity and robustness necessary to allow and withstand such large-scale conformational changes. RESULTS By biochemically mapping scaffold-binding regions of all fungal and human linker nucleoporins and determining crystal and single-particle cryo-EM structures of linker-scaffold complexes, we completed the characterization of the biochemically tractable linker-scaffold network and established its evolutionary conservation, despite considerable sequence divergence. We determined a series of crystal and single-particle cryo-EM structures of the intact Nup188 and Nup192 scaffold hubs bound to their Nic96, Nup145N, and Nup53 linker nucleoporin binding regions, revealing that both proteins form distinct question mark-shaped keystones of two evolutionarily conserved hetero‑octameric inner ring complexes. Linkers bind to scaffold surface pockets through short defined motifs, with flanking regions commonly forming additional disperse interactions that reinforce the binding. Using a structure‑guided functional analysis in Saccharomycescerevisiae, we confirmed the robustness of linker‑scaffold interactions and established the physiological relevance of our biochemical and structural findings. The near-atomic composite structures resulting from quantitative docking of experimental structures into human and S.cerevisiae cryo-ET maps of constricted and dilated NPCs structurally disambiguated the positioning of the Nup188 and Nup192 hubs in the intact fungal and human NPC and revealed the topology of the linker-scaffold network. The linker-scaffold gives rise to eight relatively rigid inner ring spokes that are flexibly interconnected to allow for the formation of lateral channels. Unexpectedly, we uncovered that linker‑scaffold interactions play an opposing role in the outer rings by forming tight cross-link staples between the eight nuclear and cytoplasmic outer ring spokes, thereby limiting the dilatory movements to the inner ring. CONCLUSION We have substantially advanced the structural and biochemical characterization of the symmetric core of the S.cerevisiae and human NPCs and determined near-atomic composite structures. The composite structures uncover the molecular mechanism by which the evolutionarily conserved linker‑scaffold establishes the NPC's integrity while simultaneously allowing for the observed plasticity of the central transport channel. The composite structures are roadmaps for the mechanistic dissection of NPC assembly and disassembly, the etiology of NPC‑associated diseases, the role of NPC dilation in nucleocytoplasmic transport of soluble and integral membrane protein cargos, and the anchoring of asymmetric nucleoporins. [Figure: see text].

Influence of thermal effects on the breakup of thin films of nanometric thickness

We apply a previously developed asymptotic model (J. Fluid. Mech. 915, A133 (2021)) to study instabilities of free surface films of nanometric thickness on thermally conductive substrates in two and three spatial dimensions. While the specific focus is on metal films exposed to laser heating, the model itself applies to any setup involving films on the nanoscale whose material parameters are temperature-dependent. For the particular case of metal films heated from above, an important aspect is that the considered heating is volumetric, since the absorption length of the applied laser pulse is comparable to the film thickness. In such a setup, absorption of thermal energy and film evolution are closely correlated and must be considered self-consistently. The asymptotic model allows for a significant simplification, which is crucial from both modeling and computational points of view, since it allows for asymptotically correct averaging of the temperature over the film thickness. We find that the properties of the thermally conductive substrate -- in particular its thickness and rate of heat loss -- play a critical role in controlling the film temperature and dynamics. The film evolution is simulated using efficient GPU-based simulations which, when combined with the developed asymptotic model, allow for fully nonlinear time-dependent simulations in large three-dimensional computational domains. In addition to uncovering the role of the substrate and its properties in determining the film evolution, one important finding is that, at least for the considered range of material parameters, strong in-plane thermal diffusion in the film results in negligible spatial variations of temperature, and the film evolution is predominantly influenced by temporal variation of film viscosity and surface tension (dictated by average film temperature), as well as thermal conductivity of the substrate.

Diffusiophoresis of a highly charged conducting fluid droplet

Diffusiophoresis of a perfectly conducting droplet-like liquid metal in electrolyte solutions is investigated theoretically, focusing on the chemiphoresis component, the very heart of diffusiophoresis, where the droplet motion is induced solely by the chemical gradient. The resulting electrokinetic equations are solved with a pseudo-spectral method based on Chebyshev polynomials. For the isothermal electrokinetic system of a perfectly conducting droplet considered here, there is no Marangoni effect, which is a motion-inducing effect due to the variation of interfacial tension along the droplet surface. No Maxwell traction is present as well. The droplet motion is full of hydrodynamic nature. It is found, among other things, that contrary to a dielectric droplet, a conducting droplet always moves up the chemical gradient toward the region with a higher concentration of ions in chemiphoresis. This implies that a perfectly conducting droplet like a gallium or its alloy droplet is superior to the commonly utilized dielectric droplet like a liposome in drug delivery in terms of self-guarding itself toward the desired destination of injured or infected area in the human body, as specific ionic chemicals are often released there. Optimum droplet size yielding the fastest migration rate is predicted.

Instantaneous identification of tension in bridge cables using synchrosqueezing wave-packet transform of acceleration responses

Real-time monitoring of cable tension is essential in detecting damage and assessing the service performance of bridges. Vibration frequency-based methods for cable tension identification have been increasingly investigated in bridge engineering over the last decade. However, cable tension estimation using vibration frequency-based methods can only obtain the average cable tension over a specified time interval. Therefore, identification of instantaneous variation of cable tension still remains to be a pending issue. To tackle this problem, this study proposes an algorithm defined as Synchrosqueezing Wave-packet-based Instantaneous Frequency Tracking (SWIFT) to identify the instantaneous change of cable tension by monitoring its acceleration responses. The proposed algorithm can extract the time-varying instantaneous frequency of the tested cable and further identify the variation of instantaneous cable tension by time-frequency analysis of the transversal motion. Moreover, the identification accuracy and noise robustness are numerically verified using a synthetic time-varying multi-frequencies signal. Finally, experimental validation is conducted on a prototype cable and an actual cable of the Sutong Yangtze River bridge, respectively. The theoretical, numerical, and experimental results show that the proposed method can precisely identify instantaneous cable tension under noisy conditions.

Instabilities in a Spherical Liquid Drop

We examine cases of stationary vortices that can appear inside spherical liquid drops in microgravity conditions. The first case is that of an incompressible external flow of uniform speed at infinity, leading the liquid in the drop by friction to form a Hill vortex. In the second case, the external fluid does not interact by friction with the liquid, but the drop is subjected to an axial temperature gradient causing a variation in surface tension. This time it is the induced movement which entrains the internal liquid. Note that the two situations can lead to the same Hill vortex. Combined effects are envisioned. We are also interested in the time factor in these phenomena.

The Impact of Reduced Gravity on Oscillatory Mixed Convective Heat Transfer around a Non-Conducting Heated Circular Cylinder

The present analysis addresses the impact of reduced gravity and magnetohydrodynamics on oscillating mixed-convective electricallyconducting fluid flow over a thermal, non-conducting horizontal circular cylinder. In reduced gravity, buoyancy forces may induce fluid motion due to a weak gravitational field but in non-gravity forces, fluid motion can be induced by a variety of factors, including surface tension and density variations. The fluid motion is governed by connected nonlinear partial differential equations which are converted into convenient equations by applying a finite-difference scheme with the primitive transformation and a Gaussian elimination technique. The numerical solutions of the connected dimensionalized equations were obtained for various emerging dimensionless parameters, reduced gravity parameter Rg, Prandtl number Pr, and some other fixed parameters. First, the fluid velocity, temperature distribution and magnetic-field profiles were obtained and then these profiles were used to examine the oscillating quantities of skinfriction, oscillating heat transfer and oscillating rate of currentdensity. The FORTRAN software was used for the numerical results and these results were displayed on Tech Plot. The fluid velocity and magnetic profile were increased at the π/2 station as reduced gravity increased but the dimensionless temperature of the fluid attained a maximum magnitude as reduced gravity was decreased. The larger amplitude of the oscillating coefficients of τt and τm was concluded with a prominent variation for each λ in the presence of reduced gravity. Physically, this could be because an increase in the decreased gravity parameter impacts the fluid flow’s driving potential along a thermal, non-conducting horizontalcylinder.

A Compound Droplet Undergoing Thermocapillary Migration Passing Through a Constricted Tube

Abstract In this paper, we numerically investigate the dynamics of a compound droplet driven by surface tension variation induced by a thermal gradient in a sinusoidal constriction tube. Initially, the compound droplet with a concentric inner core is spherical and placed in the constriction's upstream region at a low temperature. As time progresses, it migrates downstream with a high temperature. Due to the constriction, the droplet is slowed down in the upstream region and accelerated again right after passing the constriction. This acceleration maximizes the eccentricity. However, the constriction results in an increase in the maximum eccentricity when increasing its depth to a value corresponding to the size of the tube neck, which is greater than or equal to the droplet size. Effects of various parameters, e.g., the Marangoni number Ma, the capillary number Ca, and the radius ratio Rio, are studied. It is found that increasing the Ma number or decreasing the Ca number reduces the maximum eccentricity and prolongs the travel time, i.e., the arrival time, from the upstream to the downstream. A similar reduction in the maximum eccentricity also occurs with the increased Rio ratio. Effects of these parameters on the migration velocity are also revealed.

Influences of fluid physical properties, solid particles, and operating conditions on the hydrodynamics in slurry reactors

Slurry reactors are popular in many industrial processes, involved with numerous chemical and biological mixtures, solid particles with different concentrations and properties, and a wide range of operating conditions. These factors can significantly affect the hydrodynamic in the slurry reactors, having remarkable effects on the design, scale-up, and operation of the slurry reactors. This article reviews the influences of fluid physical properties, solid particles, and operating conditions on the hydrodynamics in slurry reactors. Firstly, the influence of fluid properties, including the density and viscosity of the individual liquid and gas phases and the interfacial tension, has been reviewed. Secondly, the solid particle properties (i.e., concentration, density, size, wettability, and shape) on the hydrodynamics have been discussed in detail, and some vital but often ignored features, especially the influences of particle wettability and shape, as well as the variation of surface tension because of solid concentration alteration, are highlighted in this work. Thirdly, the variations of physical properties of fluids, hydrodynamics, and bubble behavior resulted from the temperature and pressure variations are also summarized, and the indirect influences of pressure on viscosity and surface tension are addressed systematically. Finally, conclusions and perspectives of these notable influences on the design and scale-up of industrial slurry reactors are presented.

Hydrodynamic characteristics of the crane vessel-three-bucket jacket foundation coupling hoisting system during the process of lowering

In the present study, a novel three-bucket jacket foundation with air-cushion launching technology is proposed. Through the theoretical analysis and commercial hydrodynamic software Moses, a crane vessel-three-bucket jacket foundation coupling hoisting system is established, and time-domain calculations are performed accordingly. Moreover, based on statistical information of the actual sea conditions in a certain sea area throughout the year, the corresponding permissible sea conditions for the construction of the sea are calculated to provide technical guidance for practical engineering. Furthermore, the hydrodynamic characteristics of the crane vessel, the motion response of the coupling hoisting system and variations of the cable tension under different configurations and wave directions are obtained. It is found that the vibration frequencies of the crane vessel and the foundation are the same, and the phase is maintained at 180°. It is considered that when the foundation is located at the stern of the vessel and encounters transverse waves, resonance occurs between the crane vessel and the foundation, which should be avoided in actual construction.

Modeling and optimization of Wire –EDM parameters for machining of Ni54.1Ti45.9 shape memory alloy using hybrid approach

Shape memory alloys are a distinct family of alloys recognized for their unique features, such as extreme anti-fatigue, exceptional specific strength, corrosion resistance, biocompatibility, and pseudo-elasticity. Due to strain-hardening effects displayed by the latter during a conventional machining process, these features make shape memory alloys particularly functional for machining utilizing non-traditional methods rather than conventional ones. The alloy's original qualities are at risk as a result of this consequence. Nickel-Titanium shape memory alloys with 54.1 and 45.9% Nickel-Titanium blends were employed in this investigation (Ni54.1Ti45.9). The surface characteristics of Ni54.1Ti45.9 alloy are investigated using the wire electrical discharge machining (WEDM) technique with a brass tool electrode (zinc-coated) and the influence of process parameters on it. Variations in wire feed rate, wire tension, pulse on and off duration, and peak current were used as input factors to investigate variations in surface roughness and material removal rate. Surface roughness and material removal rate data from L27 orthogonal array (OA) studies were used to create artificial neural network (ANN) models. To improve the quality attributes, a model combining a hybrid version of the genetic algorithm (GA) and an ANN has been presented. The ANN models were found to accurately predict the results, which matched the experimental data. After the adjustment, the quality features also improved significantly.

Influence of Initial Guy Tension and Antenna Masses in the Sensor Layout for Dynamic Characterization of Guyed Masts

Sensitivity analysis plays an important part in the validation of a sensor layout for the identification of the dynamic response of a system. Although sensitivity analysis has been implemented for this purpose in several civil engineering structures, there are still uncertainties in the case of more complex, nonlinear systems, such as guyed masts, where small changes in mass or stiffness can result in large variations of the general dynamic behavior. This paper describes the influence of antenna masses and initial guy tension variation in the total number and position of sensors required to assess the dynamic response of tall guyed mast telecommunication towers. For the study, the computational models of four different guyed masts were generated and a sensor layout was obtained for each model using a sensitivity analysis. Then, the proposed sensor layouts were verified for different initial guy tensions and total antenna mass of the system, by means of the Modal Assurance Criterion. The principal finding is that initial guy tension presents the highest influence on the variation of correspondence values between mode shapes, with modifications of these values in up to [Formula: see text]. This finding suggests that a preliminary sensor layout based on information provided by a computational model or structural drawings of a guyed mast may be rendered inefficient if there is variation in guy tension due to construction errors or relaxation of cables.

Experiment and prediction model study on pool boiling heat transfer of water in the electric field with periodically changing direction

The pool boiling heat transfer performance of water could be greatly improved by the constant electric field with the bar electrode. While, the heat transfer of water enhanced by electric field with periodically changing direction is rarely involved. Therefore, the heat transfer performance of water, mechanism analysis and prediction model for heat transfer characteristic affected by the electric field with periodically changing direction were studied. Individually, the heat transfer coefficient (HTC) and critical heat flux (CHF) were compared. Meanwhile, the difference of droplet shape, size of contact angle, bubbles growth and detachment on heat transfer surface were analyzed. Besides, semi-empirical prediction models for HTC and CHF were proposed. Results show that the HTC and CHF are significantly enhanced with decrease of switch period. While, this enhancement is diminished with increase of heat flux. Furthermore, when compared to the constant direction electric field, mechanism analysis indicates that the electric field with periodically changing direction not only enhances the rate of boiling fluid wetting the boiling heat transfer surface, but also accelerates the growth and detachment of bubbles. Moreover, predicted curves of model agree well with the experimental data, and variation of surface tension is considered as the main factor affecting heat transfer.

Improving the staircase approximation for wettability implementation of phase-field model: Part 2 – Three-component permeation

In this study, the displacement dynamics of compound droplet inside porous medium with complex structure is numerically investigated by the newly-proposed wetting boundary treatments in Part 1 [1]. The compound droplet consists of two immiscible fluids surrounded by another fluid forming a three-phase system. To investigate the compound droplet's penetration and spreading in two regimes, the conservative phase-field model is solved via the lattice Boltzmann method (LBM) at different wettability and governing non-dimensional numbers including the Reynolds number (25-100), Weber number (100-1000), and density ratio (7.5-750). Moreover, the permeation and spreading of each droplet, without the presence of the other in the binary system, is compared with those of ternary. It is revealed that the way the penetration is influenced by the variation of surface tension, wettability, and density ratio completely depends on the value of Bond number and the capillary or gravitational-dominant regimes. Furthermore, it appears that in the capillary-dominant regime, the migration pattern of one droplet cannot be evaluated independent of the other, since the factors affecting the capillary pressure and viscous coupling on one, affects the penetration and spreading of the other. Finally, it is identified that ternary penetration is slower than binary and the presence of the other droplet confines the early stage spreading in the ternary system.

Significance of non-intraocular pressure (IOP)-related factors particularly in normal tension glaucoma: Looking beyond IOP.

Purpose:To study the relationship between intraocular pressure (IOP) and mean ocular perfusion pressure (MOPP) in patients with POAG and NTG. The secondary objective was to identify other contributory ischemic factors.Methods:This was an observational cross-sectional study from a tertiary eye hospital in patients who underwent full-day diurnal variation of tension (DVT). Blood pressure (BP) and IOP measurements were done every 3 h over 24 h. Mean arterial pressure (MAP) and MOPP were calculated. The nocturnal dip in BP was assessed; patients were classified as non-dippers, dippers, and over-dippers. The circadian MOPP fluctuation (CMF) was calculated using the Kruskal–Wallis test, and its relationship with type and severity of visual field was assessed.Results:In total, 149 patients were evaluated; 109 were classified as NTG, and 40 were classified as POAG. A nocturnal dip in BP was noted in 20% of NTG and 17.5% of POAG. The MAP was found to be lower in patients with NTG than POAG. In the NTG subgroup, we found that 20% of patients were over-dippers, 32% were dippers, and 48% were non-dippers. The CMF showed a greater fluctuation for over-dippers (P = 0.004 for the RE and 0.003 for the LE) than dippers and non-dippers. A weak positive correlation of CMF with the severity of fields was found.Conclusion:A 24-h monitoring of IOP, BP, MOPP, and assessment of systemic risk factors for primary glaucoma acts as an invaluable tool for the comprehensive management of NTG despite the limitations posed by DVT and BP recording.

Simulation of Continuous Tension Stringing Process of Conductor with Bending Stiffness Model

At present, there is no research on the calculation of tension variation of the conductor with bending stiffness model between the continuous span during tension stringing construction. Aiming at the typical terrain with large elevation difference in UHV project, a vector finite element method for calculating the tension of the conductor with bending stiffness model passes through the pulley in the process of tension stringing is proposed. The process of the wire rope under the action of the tractor pulling the conductor passes through the pulley continuously is realized. The variations of tension of tensioner and tractor, reaction force of pulley and envelope angle of the conductor passes through the pulley are obtained by simulation of tension stringing conditions such as 1 pulls 1, 1 pulls 2, etc, which provides reference for equipment selection for the tension stringing construction of mountain terrain with large elevation difference.

Cover Feature: Catch and Release Chemotaxis (ChemSystemsChem 2/2022)

The Front Cover shows the repetition of catch and release chemotaxis, which was studied by using a self-propelled 6-methylcoumarin (6-MC) disk floating on water. A tablet of Na3PO4 placed at the bottom of the water phase acted as the chemical stimulus by inducing a variation in surface tension. The self-propelled object, the 6-MC disk, moves in the direction of the chemical stimulus (top left) and it is caught by the stimulus (top right), that is, by the chemical reaction between 6-MC and OH−. When OH− is consumed, the 6-MC disk is released from the tablet and moves towards the higher surface tension (bottom). More information can be found in the Article by Masaharu Nagayama, Satoshi Nakata and co-workers.

Morphology of MoS2 nanosheets and its influence on water/oil interfacial tension: A molecular dynamics study

Plate-shaped nanoparticles exhibit huge potential for a broad range of cutting-edge applications in interfacial-based science and technology, such as enhanced oil recovery in hydrocarbon reservoirs, owing to their remarkable features in superior affinity toward interfaces. Understanding the adsorption behavior of nanosheets (NSs) self-assembled at the water/oil interface (W/O interface) is crucial to elucidate the variation of interfacial tension (IFT) and establish special design criteria for efficient industrial use of NSs. Here we present a molecular dynamics study to reveal the morphology of carbon-chain modified molybdenum disulfide (MoS2) nanosheets. The stress exerted on a nanosheet is analyzed. The simulation results demonstrate a significant decrease in interfacial tension after adding NSs to the water/oil system, followed by a noticeable fluctuation with increased NS concentration. Surprisingly, the carbon-chain modified MoS2 nanosheets do not show a greater ability in altering IFT compared to unmodified ones. The IFT fluctuation is found strongly linked to the competition between the effects of interface coverage rate of adsorbed nanosheets and the intersection angle arising from non-uniform forces acting on a nanosheet.

Surface roughness effects on a tensioned riser vortex-induced vibration in the uniform current

Due to the long-term operation of marine riser, marine organisms will adsorb on its surface, thus affect its surface roughness. The surface roughness of the riser will affect the wake flow field of the riser, and then affect the dynamic characteristics of the vortex-induced vibration (VIV). The study of the influence of surface roughness on the characteristics of a rough riser VIV is helpful to improve our understanding of the mechanism of a rough riser VIV and ensure the safety of the riser during its service life. Based on the methods of computational fluid dynamics (CFD) and computational structure dynamics (CSD), this study presents the model considering tension variation with the structure vibration and the modified model of rough wall velocity gradient to construct the numerical calculation program of a rough riser VIV to study effects of various key parameters (surface roughness, inflow velocities) on the dynamic characteristics, vibration response, wake vortex shedding patterns and vibration trajectories of a rough riser. The results show that in the range of Reynolds number Re = 2.515 × 104∼1.258×105 and reduced velocity U* = 1.35–6.74, compared with a smooth riser, the streamwise vibration amplitude of a rough riser decreases, and with the increase of inflow velocity and surface roughness, the streamwise vibration amplitude of a rough riser decreases more and more obviously. In the range of reduced velocity U* = 2.70–5.39, the transverse vibration amplitude of a rough riser increases slightly. At a higher reduced velocity (U* = 6.74), the transverse vibration amplitude of the rough riser decreases. Larger surface roughness will enhance the multi-frequency and broadband vibration characteristics of the riser in the streamwise direction. With the increase of surface roughness, the multi-frequency vibration characteristics decrease gradually, but the broadband vibration characteristics increase gradually in the transverse direction. Surface roughness can suppress 2T and 2P wake vortex shedding pattern and enhance 2C wake vortex shedding pattern. This study will provide a profound understanding to guide the practical marine riser VIV research with the consideration of surface roughness.