Vortex Intensity Research Articles

Generation of ultra-intense vortex laser from a binary phase square spiral zone plate.

With the development of ultra-intense laser technology, the manipulation of relativistic laser pulses has become progressively challenging due to the limitations of damage thresholds for traditional optical devices. In recent years, the generation and manipulation of ultra-intense vortex laser pulses by plasma has attracted a great deal of attention. Here, we propose a new scheme to produce a relativistic vortex laser. This is achieved by using a relativistic Gaussian drive laser to irradiate a plasma binary phase square spiral zone plate (BPSSZP). Based on three-dimensional particle-in-cell (3D-PIC) simulations, we find that the drive laser has a phase difference of π after passing through the BPSSZP, ultimately generating the vortex laser with unique square symmetry. Quantitatively, by employing a drive laser pulse with intensity of 1.3 × 1018~W/cm2, a vortex laser with intensity up to 1.8 × 1019~W/cm2, and energy conversion efficiency of 18.61% can be obtained. The vortex lasers generated using the BPSSZP follow the modulo-4 transmutation rule when varying the topological charge of BPSSZP. Furthermore, the plasma-based BPSSZP has exhibited robustness and the ability to withstand multiple ultra-intense laser pulses. As the vortex laser generated via the BPSSZP has high intensity and large energy conversion efficiency, our scheme may hold potential applications in the community of laser-plasma, such as particles acceleration, intense high-order vortex harmonic generation, and vortex X/γ-ray sources.

Contribution of Different Parameters on Film Cooling Efficiency Based on the Improved Orthogonal Experiment Method

The use of film cooling technology is one of the most effective ways to minimize the damage to wall materials caused by the high-temperature environment in a ramjet. Optimization of the design to achieve the highest film cooling efficiency on the hot wall is the focus of current research. Due to the large number of parameters affecting the film cooling efficiency and the interactions between them, an improved orthogonal design-of-experiments method is chosen to investigate the contribution of different parameters. Flat plate film cooling and transverse groove film cooling are simulated numerically. The results indicated that the contribution of each parameter is ranked as hole spacing (S/D) > incidence angle > blowing ratio for flat plate film cooling; hole spacing > transverse groove depth > blowing ratio > incidence angle for transverse groove film cooling. The film cooling efficiency is inversely proportional to the size of the flow field area affected by the vortex ring and directly proportional to the size of the vortex intensity. Transverse groove film cooling forms a more complete film in most cases, which is better than flat plate film cooling. Within the scope of this study, a complete film at S/D > 2.0 cannot be generated on the flat plate, which should not be used in ramjet.

Research on diffusion characteristics of liquid jet effected by shock wave in supersonic high-enthalpy crossflow

The diffusion characteristics of liquid jets with phase transition under the action of shock waves in supersonic high-enthalpy crossflow were discussed in this paper. Numerous numerical simulations were carried out in high enthalpy inflow (Tt = 1680 K) under different shock wave intensity and injection parameter conditions. The Euler-Lagrangian method was employed to solve the gas-liquid two-phase flow coupling, and the evaporation, diffusion and mixing processes of kerosene were obtained. By analyzing simulation results, the influence and the mechanism of shock waves on enhanced kerosene mixing were revealed. The results show that increasing the shock wave intensity effectively improves the penetration and mixing of kerosene in general by changing the flow state and evaporation process. The penetration depth can be increased by up to 63.54 % in this paper. To balance the contradiction between total pressure loss and mixing efficiency, it is necessary to select an appropriate shock wave intensity. The enhanced diffusion and mixing process of kerosene by shock waves are related to the injection momentum ratio, evaporation momentum ratio and streamwise vortex intensity. Weakening mainstream momentum while boosting evaporation and vortex intensity effectively strengthens kerosene diffusion and mixing. This research significantly contributes to enhancing the diffusion and mixing of liquid kerosene and improving combustor performance.

Unsteady assessment and alleviation of inter-blade vortex in Francis turbine

Inter-blade vortex refers to a specific type vortex cavitation observed in Francis turbines under partial loads and its adverse impact is widely recognized as a crucial factor that limits the safety and stability of hydraulic turbines. The present study endeavors to examine the spatiotemporal evolution attributes of inter-blade vortex and its contribution to the generation of unstable pressure fluctuations. To achieve this, a comprehensive investigation is conducted using a reduced-scale Francis model turbine with low head, combining numerical investigations and visualization experiments. The study demonstrates that the vapor volume associated with the inter-blade vortex experiences periodic pulsation, with a frequency proximate to the rotational frequency of the runner. Within the turbine runner, cavitation exhibits a dynamic cycle of incipience, growth, expansion, and localized collapse. The most remarkable cavitation disintegration occurs at the convergence point of the trailing edge of the runner blade and the band, wherein the most pronounced amplitude of pressure fluctuation is also discerned. In addition, this research establishes a direct correlation between pressure fluctuations and vapor volume, revealing that the acceleration of the vapor volume is accountable for the occurrence of pressure fluctuations with heightened magnitude. Furthermore, an optimization campaign successfully reduces the cavitation volume by 88.58% and 78.99% at two specific points of interest, resulting in the nearly complete elimination of high-amplitude pressure pulsations. Building upon these findings, data mining techniques are implemented to identify that the blade profile at a spanwise height of 0.75 significantly influences the enhancement of turbine hydraulic performance. Additionally, it has been ascertained that the design parameter governing the geometric placement of the blade trailing edge plays a pivotal role in reducing the intensity of the inter-blade vortex. This study yields invaluable insights into the underlying mechanism of unsteady phenomena induced by inter-blade vortex and formulates a hydraulic optimization approach capable of enhancing the operating stability of the Francis turbine.

Efficient generation and amplification of intense vortex and vector laser pulses via strongly-coupled stimulated Brillouin scattering in plasmas

The past decade has seen tremendous progress in the production and utilization of vortex and vector laser pulses. Although both are considered as structured light beams, the vortex lasers have helical phase fronts and phase singularities, while the vector lasers have spatially variable polarization states and polarization singularities. In contrast to the vortex pulses that carry orbital angular momentum (OAM), the vector laser pulses have a complex spin angular momentum (SAM) and OAM coupling. Despite many potential applications enabled by such pulses, the generation of high-power/-intensity vortex and vector beams remains challenging. Here, we demonstrate using theory and three-dimensional simulations that the strongly-coupled stimulated Brillouin scattering (SC-SBS) process in plasmas can be used as a promising amplification technique with up to 65% energy transfer efficiency from the pump beam to the seed beam for both vortex and vector pulses. We also show that SC-SBS is strongly polarization-dependent in plasmas, enabling an all-optical polarization control of the amplified seed beam. Additionally, the interaction of such structured lasers with plasmas leads to various angular momentum couplings and decouplings that produce intense new light structures with controllable OAM and SAM. This scheme paves the way for novel optical devices such as plasma-based amplifiers and light field manipulators.

Study on flow field characteristics of gas-liquid hydrocyclone separation under vibration conditions.

The complex vibration phenomenon occurs in the downhole environment of the gas-liquid hydrocyclone, which affects the flow field in the hydrocyclone. In order to study the influence of vibration on hydrocyclone separation, the characteristics of the flow field in the downhole gas-liquid hydrocyclone were analyzed and studied under the condition of vibration coupling. Based on Computational Fluid Dynamics (CFD), Computational Solid Mechanics Method (CSM) and fluid-solid coupling method, a fluid-solid coupling mechanical model of a gas-liquid cyclone is established. It is found that under the condition of vibration coupling, the velocity components in the three directions of the hydrocyclone flow field change obviously. The peak values of tangential velocity and axial velocity decrease, and the asymmetry of radial velocity increases. The distribution regularity of vorticity and turbulence intensity in the overflow pipe becomes worse. Among them, the vorticity intensity of the overflow pipe is obviously enhanced, and the higher turbulence intensity near the wall occupies more area distribution range. The gas-liquid separation efficiency of the hydrocyclone will decrease with the increase of the rotational speed of the screw pump, and the degree of reduction can reach more than 10%. However, this effect will decrease with the increase of the rotational speed of the screw pump, so the excitation effect caused by the rotational speed has a maximum limit on the flow field.

Vortex dynamics characteristics in the tip region based on Wray–Agarwal model

In order to solve the blockage effect and energy dissipation phenomenon caused by cavitation in the low-pressure vortex core region, this paper analyzes the spatial evolution of vorticity intensity and turbulent kinetic energy intensity under different cavitation conditions based on the Wray–Agarwal (WA) model. First, the tip leakage flow characteristics are studied, the evolution of vorticity and vorticity intensity is analyzed, then the distribution of turbulent kinetic energy distribution in the blade tip region is studied, and finally, the vorticity transport characteristics of the tip region are analyzed. It is found that the tip leakage rate is less affected by the vortex cavitation of the tip leakage, and there is a strong interaction between the leakage flow at the tip leading edge and the trailing edge, and the separation vortices and low-speed regions formed in the end-wall region cause blockage of the flow passage. Low pressure causes cavitation to cover most regions of the suction surface, inhibiting the formation and development of the tip leakage vortices. The distribution range of high turbulent kinetic energy region is almost the same as that of high-vorticity region, and there is a positive correlation between the two intensities. Severe cavitation causes the high turbulent kinetic energy region at the outlet of the flow passage to develop in the radial and axial directions of the impeller, which increases the turbulent dissipation and energy loss. The change of vorticity transport intensity caused by cavitation is mainly reflected in the expansion contraction term, and the Coriolis force term plays a dominant role in the vorticity transport process. This paper provides a reference for further improving the performance of mixed-flow pumps.

An Observational Analysis of the Relationship between Tropical Cyclone Vortex Tilt, Precipitation Structure, and Intensity Change

Abstract This study uses a recently developed airborne Doppler radar database to explore how vortex misalignment is related to tropical cyclone (TC) precipitation structure and intensity change. It is found that for relatively weak TCs, defined here as storms with a peak 10-m wind of 65 kt (1 kt = 0.51 m s−1) or less, the magnitude of vortex tilt is closely linked to the rate of subsequent TC intensity change, especially over the next 12–36 h. In strong TCs, defined as storms with a peak 10-m wind greater than 65 kt, vortex tilt magnitude is only weakly correlated with TC intensity change. Based on these findings, this study focuses on how vortex tilt is related to TC precipitation structure and intensity change in weak TCs. To illustrate how the TC precipitation structure is related to the magnitude of vortex misalignment, weak TCs are divided into two groups: small-tilt and large-tilt TCs. In large-tilt TCs, storms display a relatively large radius of maximum wind, the precipitation structure is asymmetric, and convection occurs more frequently near the midtropospheric TC center than the lower-tropospheric TC center. Alternatively, small-tilt TCs exhibit a greater areal coverage of precipitation inward of a relatively small radius of maximum wind. Greater rates of TC intensification, including rapid intensification, are shown to occur preferentially for TCs with greater vertical alignment and storms in relatively favorable environments. Significance Statement Accurately predicting tropical cyclone (TC) intensity change is challenging. This is particularly true for storms that undergo rapid intensity changes. Recent numerical modeling studies have suggested that vortex vertical alignment commonly precedes the onset of rapid intensification; however, this consensus is not unanimous. Until now, there has not been a systematic observational analysis of the relationship between vortex misalignment and TC intensity change. This study addresses this gap using a recently developed airborne radar database. We show that the degree of vortex misalignment is a useful predictor for TC intensity change, but primarily for weak storms. In these cases, more aligned TCs exhibit precipitation patterns that favor greater intensification rates. Future work should explore the causes of changes in vortex alignment.

STABILITY OF LIQUID-LIQUID INTERFACE IN UNEVENLY ROTATING HORIZONTAL CYLINDERS

The effect of rotational velocity modulation on the shape of the interface between liquids with high contrast of viscosities and of different densities in a rapidly rotating horizontal cylinder is experimentally investigated. During rotation, the more viscous fluid with higher density is located near the lateral boundary of the cavity, and it is found that modulation of the rotation rate leads to the loss of stability of the initially axisymmetric liquid-liquid interface. The instability manifests itself in the development of a spatially periodic quasi-stationary 2D "frozen" wavy pattern on the interface. The phenomenon has a threshold character; the critical amplitude of velocity modulation depends on the rotation rate and the frequency of velocity modulation. It is shown that the appearance of the frozen waves is associated with the Kelvin-Helmholtz oscillatory instability and is accompanied by the generation of intensive vortex flows near the interphase boundary.

Review of studies on the distribution of Antarctic krill accumulations in the Scotia Sea and analysis of mesoscale dynamics of its habitat

This article studies the mesoscale dynamics of the waters of the Scotia Sea, located at the northern tip of the Southern Ocean on its border with the Southern Atlantic Ocean. The Scotia Sea is one of the most promising fishing areas where the industrial catch of Antarctic krill (Euphausia superba) is produced. Since the distribution of commercial krill accumulations is largely determined by oceanological conditions, this paper analyzes mesoscale vortex dynamics, frontal zones, and topography in the Scotia Sea, affecting the creation of favorable oceanological conditions for the formation of commercial krill accumulations. The study is conducted using satellite and model data. It is shown that the distribution of sea level according to the GLORYS12v1 reanalysis data in the Scotia Sea has a zonal character. In winter and spring, sea level anomalies are positive (up to 20 cm), and in summer and autumn, they are negative (up to -180 cm). In the northwestern part of the Scotia Sea, according to the data of the GLORYS12v1 reanalysis for 1993-2020, thermal frontal zones with high repeatability (> 80%) are distinguished. Dynamic frontal zones are also distinguished in the northwestern part of the water area and have a repeatability reaching 100%. This area in the Scotia Sea is the most dynamically active: increased kinetic energy values are observed here. The increased dynamic activity in the northwestern part of the Scotia Sea, considered above by the average and average seasonal distributions of characteristics, is also confirmed in the synoptic range of periods. Spatial distributions of long-lived mesoscale vortices according to META 3.2 data for 1993-2021 show the localization areas of these vortices, with cyclones forming significantly more than anticyclones. Analysis of the trajectories of these vortices showed that the direction of their propagation is mainly eastern. The intense vortex dynamics in the Scotia Sea is also confirmed by reconstructed altimetric data for 1970-1992.

Wavefront distortion and compensation for weakly relativistic vortex beams propagating in plasma

The propagation of electromagnetic wave in plasma is one of the long-standing concerns in the field of laser plasma, and it is closely related to the researches of radiation source generation, particle acceleration, and inertial confinement fusion. Recently, the proposal of various schemes for generating intense vortex beams has led to an increasing number of researchers focusing on the interaction between intense vortex beams and plasmas, resulting in significant research progress in various areas, such as particle acceleration, high-order harmonic generation, quasi-static self-generated magnetic fields, and parametric instability. Compared with traditional Gaussian beams, vortex beams, featuring their hollow amplitudes and helical phases, can exhibit novel phenomena during propagating through plasma. In this work, we primarily focus on studying the influence of the propagation process on the wave structure of vortex beams before filamentation occurs. The three-dimensional particle-in-cell simulations show that weakly relativistic vortex beams exhibit wavefront distortion during their propagation in plasma. The distortion degree is closely related to the intensity of the electromagnetic wave and the propagation distance for a given plasma density. This phenomenon is theoretically explained by using a phase correction model that considers the relativistic mass correction of electrons. Additionally, we demonstrate that the wavefront distortion can be compensated for and suppressed by appropriately modulating the initial plasma density, as confirmed by three-dimensional particle simulations. The results of decomposing the wavefront into Laguerre-Gaussian (LG) mode components indicate that the wavefront distortion is primarily caused by high-order <i>p</i> LG modes, and it is independent of other <i>l</i> LG modes. Additionally, we extend the present investigation to the propagation of vortex beams in axially magnetized plasma, where the phase correction model can also effectively explain the occurrence of wavefront distortion. Our work can deepen the understanding of the interaction between plasma and strong vortex beams, and provide some valuable references for designing plasma devices serving as the manipulation of intense vortex beams in future research.

对流层北极极涡强度和形态的年代际变化及其季节性特征

对流层北极极涡强度和形态的年代际变化及其季节性特征

Effect of the Return-channel Geometric Parameters on the Performance of a Centrifugal Compressor with a High-flow Coefficient

The return-channel of a preceding stage in a multi-stage centrifugal compressor has a significant effect on the aerodynamic performance of the current and subsequent stages. However, due to the relatively complex nature of the return-channel configuration with many geometric parameters, no general design guidance is available in the literature. In this study, numerical methods are used to study the effects of different geometric parameters of a return-channel on the performance of a high-flow-coefficient centrifugal compressor. A multi-objective genetic algorithm is applied to optimize the return-channel. The effects of different geometric parameters on the performance are then studied using a sensitivity analysis method. Calculation results show that the residual vortex intensity at the outlet of the return-channel is affected by the geometric angles of the inlet and outlet of the return-channel blades. The flow uniformity at the stage outlet is primarily affected by the geometric angle of the blade outlet and the number of blades. The overall performance of the compressor stage is primarily affected by the geometric angle of the blade inlet and the lateral inclination angle of the cover plate. Calculation results for a two-stage compressor consisting of the optimized first stage and its following stage show that the outlet flow field of the first stage is more uniform than the original first stage. Additionally, at the design operating condition, the polytropic efficiency and pressure ratio of the entire unit increase by 1.07% and 4.07%, respectively. The polytropic efficiency and pressure ratio for the second stage increase by 2.34% and 3.51%, respectively. The impeller head coefficient increases by 7.33%. The theoretical analysis shows that for high-flow-coefficient centrifugal compressors, reducing the residual vortex intensity of the outlet flow field of the return-channel in a stage can significantly improve the off-design performance of the following stage.

Effects of Floating Debris on Flow Characteristics around Slotted Bridge Piers: A Numerical Simulation

Bridge pier scouring is a significant concern in hydraulic engineering, requiring thorough investigation under various conditions to estimate maximum scour depth and mitigate the risk of bridge failure. This study aims to conduct a numerical simulation of flow around a bridge pier with slots in the presence of floating debris, with the objective of analyzing variations in parameters such as velocity, shear stress, turbulent intensity, and turbulent kinetic energy. The FLOW−3D software package (Version 11), along with the k−ε (RNG) turbulence model, was employed for the simulation. The results indicate that the presence of a slot in the bridge pier provided a smooth pathway for the flow, resulting in a reduction in the pressure gradient and alleviating the negative impacts on the flow. This, in turn, led to a decrease in the velocity of the flow. Additionally, turbulence intensity around the pier ranges between 0 and 49, while turbulent kinetic energy varies from 0 to 0.005. The findings reveal that models without slots exhibit higher turbulence and vorticity levels, as well as greater flow separation, compared to models with slots. This disparity can be attributed to the slot’s ability to neutralize detrimental lateral and downward flows. Furthermore, the results demonstrate a gradual decrease in shear stress as the flow approaches slotted bridge piers, accompanied by a reduction in vortex intensity. These findings suggest that the accumulation of floating debris can counteract the influence of slots in reducing scour around bridge piers, necessitating thorough consideration during the design phase.

Comparisons on the thermal and entropic performance of helical tubes with varying cross-sections with constant wall temperature

This study investigates the thermal-hydraulic behavior of helical tubes with different cross-section types. The flow was considered to be in a turbulent flow regime, and the wall temperature of the tube was considered to be constant. Circle, horizontal oval, vertical oval, square, horizontal rectangle, vertical rectangle, equilateral triangle, and hexagons were eight cross-section types assessed in this study. Findings demonstrated that across the evaluated range of mass flow rates, cases with triangular cross-sections had the highest friction factor values. Also, it was observed that these cases have the largest and the most intense vorticity among all other cases. It was revealed that cases with sharp regions include vortices that increase the loss of kinetic energy. In circular cross-section and triangular cross-section examples, the Nu number was most varied. There is a 58% difference between maximum Nu values for circular and triangular cross-sections. The case with a circular cross-section and a mass flow rate of 2 kg/s exhibited the highest PEC factor value of approximately 1.001. Finally, it was determined that a circle cross-section is the best according to the first law of thermodynamics, but a triangular cross-section performed 52% better when compared to other cross-section forms according to the second law of thermodynamics.

Phase-matching of high-order harmonic generation in the extreme ultraviolet region with orbital angular momentum.

High-order harmonics can generate vortex beams with orbital angular momentum (OAM) in the extreme ultraviolet region. However, experimental research on their phase-matching (PM) characteristics is limited. In this study, vortex high-order harmonic generation (HHG) in the extreme ultraviolet region was generated with Ar gas. Phase-matched HHG with OAM was obtained by optimizing the focus position, laser energy, and gas pressure. The dependence of the PM characteristics on these parameters was analyzed. In addition, we conducted an experimental analysis of the dimensional properties of vortex harmonics under PM conditions. This study is a contribution towards the intense vortex high-order harmonic light sources and their applications.

Task-Driven Path Planning for Unmanned Aerial Vehicle-Based Bridge Inspection in Wind Fields

Using unmanned aerial vehicles (UAVs) for bridge inspection is becoming increasingly popular due to its ability to improve efficiency and ensure the safety of monitoring personnel. Compared to traditional manual monitoring methods, UAV inspections are a safer and more efficient alternative. This paper examines the impact of meteorological conditions on UAV-based bridge monitoring during specific tasks, with the aim of enhancing the safety of the UAV’s costly components. The wake vortex behind a bridge structure can vary over time due to airflow, which can have a direct impact on the safety of UAV flights. To assess this impact, numerical analysis is conducted based on monitoring requirements specific to different tasks, taking into account wind speed, wind direction, and air temperature. In order to optimize UAV trajectory, it is important to consider the wake vortex intensity and its associated influence region, which can pose a potential danger to UAV flight. Additionally, the analysis should take into account the aerodynamic effects of different types of bridge columns on the wake vortex. An optimization algorithm was utilized to optimize the trajectory of a UAV during bridge inspections within the safe region affected by wind fields. This resulted in the determination of an effective and safe flight path. The study reveals that varying wind speeds have an impact on the safe flight zone of UAVs, even if they are below the operational requirements. Therefore, when monitoring bridges using UAVs, it is important to take into account the influence of meteorological conditions. Furthermore, it was observed that the flight path of UAVs during square cylinder column monitoring is longer and more time-consuming than round cylinder column monitoring. Determining an effective UAV inspection path is crucial for completing bridge monitoring tasks in windy conditions, establishing bridge inspection standards, and developing the Intelligent Bridge Inspection System (IBIS).

Numerical simulation and experiment of a bypass dual throat nozzle with tab modification

Bypass dual throat nozzle (BDTN) is a new kind of fluidic thrust vectoring nozzle that can provide thrust vectoring by controlling self-adaptive flow. In this paper, BDTN-tab is proposed to improve the mixing ability of the nozzle. It is defined as a new kind of BDTN with an outlet modified by a pair of tabs. Under the premise of ensuring the nozzle outlet projected area remains unchanged, the pair of tabs coplanar with the convergent section of the cavity is designed to be. This design takes aerodynamic performance, thrust vectoring performance and mixing ability into account. Conclusions can be drawn through theoretical analysis, design, numerical simulation and wind tunnel experiments: The BDTN-tab can produce a thrust vectoring angle by opening the bypass valve, which can reach an extreme angle of 32°. As the tab angle increases, the thrust coefficient and thrust vectoring angle of the nozzle decrease. However, the vortex intensity at the nozzle outlet increases and can enhance the mixing between primary flow and external flow.

Tip leakage flow of a vibrating airfoil in a linear compressor cascade

In turbomachinery, understanding the interaction between blade vibrations and the tip flow is of great interest due to current trends, which tend to thinner airfoils with higher loading and higher efficiencies. The present paper experimentally investigates the unsteady tip leakage flow/vortex (TLF/V) of a vibrating airfoil in a compressor cascade with a large tip gap subjected to bend-mode controlled oscillations. Tip wall pressure distribution and secondary tip flow in the blade channel were studied using high-response pressure measurements and stereoscopic particle image velocimetry. The effects of blade vibrations on the TLF field and the TLV wandering characteristics are explored. The experimental results demonstrate that the TLF field is dominated by the TLV, and the TLV synchronously wanders with the displacement of the blade. Besides, the vortex intensity, the vortex wandering intensity, and turbulence fluctuations are phase-shifted by π/2 concerning the displacement of the blade. In contrast, the velocity deficit in the vortex core is not influenced by blade vibrations. This study provides the phase-resolved tip flow field of a vibrating airfoil with tip gaps in a linear compressor cascade, which is a necessary step toward compressor blade vibration prediction.

Innovative coatings for reducing flow-induced cylinder noise by altering the sound diffraction

The aerodynamic noise radiated by the flow past a cylinder in the subcritical regime can be modeled by a quadrupolar sound source placed at the onset position of the vortex-shedding instability that is scattered by the surface with a dipolar directivity. When the cylinder is coated with a porous material, the intensity of the shed vortices is greatly reduced, determining a downstream shift of the instability-outbreak location. Consequently, sound diffraction is less efficient, and noise is mitigated. In this paper, an innovative design approach for a flow-permeable coating based on a further enhancement of such an effect is proposed. The results of phased-microphone-array measurements show that, once the leeward part of the cover is integrated with components that make the flow within the porous medium more streamlined, the quadrupolar source associated with the vortex-shedding onset is displaced more downstream, yielding additional noise attenuation of up to 10 dB with respect to a uniform coating. Furthermore, the same noise-control mechanism based on the weakening of the sound scattering can be exploited when these components are connected to the bare cylinder without the porous cover. In this case, the mitigation of overall sound pressure levels is comparable to that induced by the coated configurations due to the lack of noise increase produced by the inner flow interacting within the pores of the material. Remarkable sound reductions of up to 10 dB and a potential drag-force decrease are achieved with this approach, which paves the way for disruptive and more optimized noise-attenuation solutions.