Incoming Flow Research Articles

Study on aerodynamic performance of floating offshore wind turbine with fusion winglets under yaw motion

ABSTRACT Floating offshore wind turbines (FOWTs) are subject to the effects of waves, currents, and wind, which induced the platform's six degrees of freedom motion affects the aerodynamic performance of FOWTs. The yaw motion not only changes the incidence angle of the incoming flow, but also adds an angular velocity to the blades. Numerous studies have shown that winglets can increase the blade's total aerodynamic efficiency. This paper investigates the aerodynamic performance of FOWTs with fusion winglets during yaw motion. The findings demonstrate that the effect of changing frequency on wind turbine power is more significant at high amplitude conditions, when the frequency is increased from 0.1 Hz to 0.2 Hz with the amplitude of 6°, the average power growth rate of the wind turbine with winglets is 3.91% higher than the average power growth rate of the wind turbine without winglets.

Dust deposition characteristics on photovoltaic arrays investigated through wind tunnel experiments

Optimizing the installation parameters of photovoltaic panels in a photovoltaic array to reduce dust accumulation, thereby enhancing their power generation, is a crucial research topic in the construction of solar power stations in desert regions. Utilizing a series of wind tunnel experiments on a photovoltaic array comprising four equally sized panels, this study assessed how variations in tilt angle, mounting height, spacing, and incoming flow direction influence both the accumulation mass of dust and the particle size distribution in a photovoltaic array. The results indicate that the dust accumulation on the first panel exponential growth with increasing tilt angle, incoming flow angles, and height, while subsequent panels displayed a trend of initial increase followed by a decrease, with a maximum increasing ratio achieved at specific installation configurations, the difference of dust mass on each panel can even be several times. Notably, when the spacing between panels exceeds twice the panel height, the mutual influence on dust deposition becomes negligible, providing a quantifiable threshold for optimal panel spacing. Additionally, significant differences exist in the particle size characteristics of dust in the panel of the array, influenced by the installation parameters of panels and the direction of the incoming flow. This research not only enhances the understanding of dust accumulation in solar energy systems but also offers practical recommendations for optimizing installation strategies, thereby improving the economic viability of solar power stations, particularly in desert regions.

Incoming flow calculation in Nam Theun 2 Reservoir

Laos is a country with a humid tropical climate, consisting of two seasons: the rainy season and the dry season. The southwest monsoon influences the region from mid-May to early October, while the northeast monsoon affects the area from early November to mid-March. Generally, the average annual rainfall ranges from 1400 mm to 2500 mm and exceeds 3500 mm in the central and southern regions. In September 2018, a hydroelectric dam encountered issues, causing part of the dam to collapse in southern Laos, Attapeu province. This disaster resulted in severe damage, with 98 people missing and 6,600 people displaced. In early September 2024, northern Laos experienced sudden flooding in Luang Namtha province, causing significant property damage. Additionally, heavy rainfall influenced by Typhoon Yagi led to the release of water from northern Laos dams for safety, including Nam Tha, Nam Ou, Nam Lik, Nam Khan 2-3, and Xayaburi dams. The issues arose from heavy rainfall and miscalculations in water flow into reservoirs, particularly in dam water management to provide early warning information to downstream communities. The purpose of this study is to assess the accuracy of the Intergrade Flood Analysis System (IFAS) model in calculating water inflow into reservoirs, specifically Nam Theun 2, to support to the water management and prevent flood-related issues. The performance of the IFAS model result used NSE (Nash-Sutcliffe efficiency), PBIAS (percent bias), R2 (coefficient of determination), and RSR (root mean square error) to compare calculated by IFAS and the water balance from 2010 to 2024, with results of NSE = 0.58, PBIAS = 8.79, R2 = 0.68, and RSR = 0.65. The 2023 study showed the highest accuracy with NSE = 0.73, PBIAS = -12, R2 = 0.83, and RSR = 0.52, Ev = 9.6 % The findings concluded that the IFAS model can calculate daily water inflow but has limitations in calculating peak and the extreme climate dry condition, such as in 2020 and 2022.

Determining The Conditions For The Efficient Use Of Resources In The Warehouse System

Abstract. Problem. For manufacturing enterprises, it is very important to reduce production and logistics costs, and one of the resource-intensive elements of this system is warehousing. Therefore, the need to establish conditions for the efficient use of material and warehouse resources is identified. Goal. The goal is to reduce the total cost of operating the built warehouse system by introducing efficient conditions for the use of resources. Methodology. A structural model of the warehouse system elements has been developed, which takes into account the main features of technological interaction of subsystems for processing incoming, internal and external flows of containers, packaging and finished products. To determine the conditions for efficient use of resources in the functioning of the warehouse system, it is proposed to use the evaluation parameter - the total cost of the warehouse system of a production enterprise. The parameters of external influence are the following intensities of flows determined by the warehouse process of a manufacturing enterprise: input, internal, and output. It is proposed to consider three options for the use of human and material resources. Originality. The article develops forecasting models of a degree type for three proposed three variants of use of material and human resources in functioning of warehouse systems of production enterprises. The obtained dependencies allow obtaining decisionmaking conditions depending on the intensity of incoming, internal and outgoing cargo flows. Practical value. Determining the conditions for using resources at the lowest possible total cost. The least costly option is to use two operators in each warehouse subsystem and one mechanism

Aerodynamic Characteristics of Cruciform Parachute with an Asymmetric Configuration of Ropes

In this study, an aerodynamic control scheme was proposed based on an asymmetric configuration of the ropes of a cruciform parachute to provide the lateral aerodynamic control forces required for it. Wind tunnel tests were conducted to confirm that this scheme could generate a lateral aerodynamic force for the cruciform parachute that was approximately 24% of the axial force. The deployment of a cruciform parachute under a subsonic flow regime was simulated by coupling the lattice Boltzmann method with a structural model. The shape of the canopy obtained from the coupled calculations was in good agreement with that determined based on the results of the wind tunnel test. The results of both showed that the cruciform parachute tilted along the direction of the shortened ropes under the combined action of the asymmetric configuration and incoming flow. This led to a difference in the lateral pressure on the canopy that led to the generation of lateral aerodynamic forces, which were linearly related to the reduced length of the ropes, and increased as their length decreased.

Early pregnancy diagnosis in cows using corpus luteum blood flow analysis based on colour Doppler ultrasonography and mRNA analysis

BackgroundReproductive efficiency is paramount in the dairy industry, where early pregnancy detection of dairy cows will allow to detect the non-pregnant animals early, thus enabling to re-synchronize them and getting them pregnant leading to decrease in calving interval, which, in turn, is critical for maximizing productivity and economic gain. The objective of this study was to evaluate the colour Doppler ultrasonography (CDUS) and peripheral blood leukocytes (PBLs)-based pregnancy-associated biomarker mRNAs expression for the earliest detection of pregnancy status in the dairy cows at post insemination. Intensively managed animals were ovulation synchronized and subjected to timed artificial insemination (TAI). On day 20, corpus luteum blood flow (CLBF) was evaluated using CDUS in 30 cows. The percentage of the incoming blood flow (as an area) of the corpus luteum (CL) was determined using an image analysis software. On day 35, the same operator performed a final pregnancy diagnosis using transrectal ultrasonography to confirm the pregnancy. Blood samples were collected on day 20 and 28 after TAI for biomarkers analysis. The mRNA expression levels of ISG15, MX1, MX2, and PAG9 genes in PBLs were determined by quantitative polymerase chain reaction (qPCR).ResultsThe identified CLBF cutoff point resulted 100% sensitivity and negative predictive value (NPV) in determining non-pregnant status on day 20 in the cows. Overall, MX2 and ISG15 mRNAs showed the most significant (P < 0.05) expression levels in pregnant animals on day 20 and 28 compared to non-pregnant animals. Among them, MX2 showed the highest expression levels on both days, ascertaining it as the better candidate biomarker for the earliest identification of pregnancy.ConclusionsThe CDUS-based CLBF analysis on day 20 after TAI can be potentially used for the early identification of non-pregnancy status in dairy cows and MX2 could be a potential mRNA candidate for the identification of pregnancy in cows. Further studies should be conducted in large scale to validate these findings due to the small sample number used in the current study.

The influence of the slit size and spacing on the impact dynamics of dry granular flows on slit dams

Slit dams play a crucial role in mitigating natural granular flows in the form of geophysical mass movements. The accurate estimation of the maximum force experienced by slit dams is a vital consideration in their design. However, understanding of the coupled influence of the incoming flow conditions and dam geometry, specifically the slit size and spacing, on the granular flow impact characteristics and forces remain incomplete. In this research, the Discrete Element Method (DEM) is used to simulate the interaction process between gravity-driven granular flows and slit dams with varying slit sizes and slit spacing. Impact characteristics are evaluated from the forces and pressures experienced by the barrier that falls between two slits, here called the divider. For a constant divider size, increasing the slit size amplifies the maximum impact force. However, once it exceeds a threshold size, enlarging the slit size diminishes the force due to a restriction from run-up height. Conversely, maintaining a constant slit size while increasing the divider size weakens the force. The influence of the slit and divider size and incoming flow conditions on the maximum force are summarized by a scaling relationship that captures the linear dependence of the impact force on the ratio of slit and divider size. Pressure distribution models are further proposed based on this scaling relationship. These outcomes provide new insights for the design of effective flow-resisting slit dams.

Experimental and Numerical Investigations of the Sediment Abrasion Mechanism at the Leading Edge of an Airfoil

Multiple engineering projects have confirmed that hydraulic machinery operating in sediment-laden rivers undergoes sediment abrasion. Guide vanes are among the most severely worn flow-passing components and have long been a key research focus in hydraulic machinery. In this research, a wear test of the NACA0012 cascade under a 10° incoming flow angle was carried out in the Venturi test system, and the evolution process of the wear was analyzed. The three-dimensional flow channel of the cascade was constructed, and the Finnie wear model was adopted for computational fluid dynamics (CFD) simulations to analyze the wear mechanism at the initial stage. The results indicate that abrasion primarily occurs at the airfoil’s leading edge and progresses through three stages: initiation, development, and stabilization. The calculated results closely matched the latest wear outcomes: In the initial stage, the wear rate density was influenced by the particle impact velocity, angle, volume fraction, and y-direction shear stress. A low-velocity zone near the impact point, combined with rebounding particles causing secondary impacts, increases the particle volume fraction and wear rate density. These secondary impacts are the primary causes of erosion on both the upstream and downstream surfaces. Furthermore, flow separation downstream from the leading edge makes this region highly susceptible to wear. This study provides valuable insights for addressing wear in hydraulic machinery for practical engineering applications.

Analytical method for analyzing message transmission processes in FDDI networks for digital substations

Objectives. To develop analytical approaches for the evaluation of probability-time characteristics and fiber distributed data interface (FDDI) network performance with the marker access method, thus enabling communication processes for digital electrical substations to be automated.Methods. The authors used theory reliability methods, random process theory, mass maintenance theory, the Laplace–Stieltjes transformation for inferring functional equations and the probability-time characteristics calculation for the information transfer processes with the occurring failures.Results. We conducted a numerical study of packet transfer processes between central processing stations in the FDDI network. We considered the processes of discrete information exchange between electronic devices in the system of electrical digital substations. These included the main technological operations and electrical digital substations operator performed when preparing reports. We described the different modes of operation, both for the individual electrical digital substation and for the system. The authors calculated node loading dependencies, FDDI network performance and temporal characteristics of the packet transfer processes on the incoming message flow intensity and the transmission medium reliability. We conducted a functional analysis of the FDDI networks on two fiber-optic rings which form the main and redundant path of data transfer between the network nodes, significantly increasing network resiliency. The objective of the study was to analyze the information transfer processes in FDDI networks with an accent on ensuring the transmission medium reliability.Conclusions. We were able to establish the existence of the critical operating network region, which leads to a sharp increase in node load and temporal characteristics, while performance reaches its maximum value and then sharply decreases. We propose the exchange of discrete messages to reflect the electronic devices state and information messages of operator between various remotely spaced electrical digital substation with the FDDI fiber-optic network.

Physical processes explaining the second force peak generated during a surge impact on a vertical wall

This paper presents an in-depth study of the impact of a surge on a vertical wall using incompressible and compressible RANS model simulations of a classical dam break experiment over a dry bed. The model allows access to the detailed flow structure and pressure field at any instant, which provides valuable complementary information to measurements. Our study focuses on the second force peak, which is often the largest one and for which the literature does not really provide a clear explanation. Before and after this peak, the pressure on the wall is governed by the flow kinematics in the area. Before the peak, an overpressure appears at the root of the reflected jet, corresponding to the violent interaction between the incoming surge and the run-down flow. At the peak instant, the situation suddenly changes, due to the collapse of the reflected jet onto the incoming flow, trapping an air cavity. As in the classical case of direct wave impact on a wall with a trapped air pocket, this process generates an additional strong uniform pressure field in the air cavity, which propagates to the water and nearby boundaries due to the water confinement effect. This compressible effect, which varies depending on the capacity of air to escape the cavity, explains the formation of the second force peak. Finally, the 3D incompressible model provides a much more reliable estimate of the second force peak than the 2D incompressible model. This is likely due to the air escape phenomenon, which occurs when the experimental initial conditions are not perfectly 2D. Although it is unlikely that the 3D simulation perfectly reproduces the experimental flow, nevertheless, with more or less comparable air escape, the computation results appear consistent.

Hydrodynamic Analysis of Flow Stabilization Process in a Miniature Circulating Water Channel Equipped with Combined Porous Plate Structures

As a foundational platform for fluid dynamics research on underwater devices, the quality of stable and uniform incoming flow in a circulating water channel (CWC) is essential. Due to the inherent structural characteristics of porous media, their application has become widespread in offshore and marine engineering. This study presents the design of a miniature circulating water channel, alongside the development of a computational fluid dynamics (CFD) numerical model to simulate the interaction between porous media and incoming flow. By analyzing the pressure loss of fluid within the porous plates and incorporating it as a source term in the momentum equation, heavy computational costs associated with fine mesh requirements in micro porous models were avoided. Simulations were conducted to investigate the effects of combined porous plates on the flow field, and the porous media model was validated by comparisons with experimental data. The distribution of the flow field within the channel was analyzed to define the test section, which was conducive to further structural optimization. The results indicated that the combined porous plates stabilized the flow field of the CWC, and, following structural optimization, the occurrence of backflow was reduced, thereby expanding the effective test section range.

Simulation study of aerodynamic ablation characteristics of ballistic missile laser fuzes

Abstract When a ballistic missile re-enters the atmosphere at hypersonic speed, the warhead and the incoming flow have a violent effect, resulting in a rapid increase in the air temperature of the surrounding flow field, and the persistent high temperature will make the optical window of the ballistic laser fuzes appear ablation phenomenon, which seriously affects the ranging accuracy of the laser detection system. In this paper, the optical window of the laser fuze is taken as the research object, quartz glass is chosen as the optical window material, and the thermal response of the optical window of the laser fuze detection system is numerically simulated according to the heat flux density parameter of the ballistic missile when it re-enters the atmosphere. The simulation results show that the quartz glass as the optical window has good ablation resistance and thermal insulation performance.

Flow-induced buckling of a bistable beam in uniform flow

Recent developments in soft materials enable the design and manufacturing of bistable flexible structures. Their fast snap-through buckling mechanisms have been utilized to introduce fast locomotion. In this paper, we aim to understand the impact of fluid–structure interaction (FSI) on the dynamics of bistable structures. We report the numerical analysis of the snap-through buckling phenomena for several bistable flexible structures fixed at both ends. The motion is driven by the fluid loading of different flow speeds. The large deformation of the bistable structure is coupled with the incoming fluid flow via the Arbitrary Lagrangian–Eulerian (ALE) method. During the snap-through buckling process, the corresponding structural deformation patterns, hydrodynamic force distributions, and fluid patterns are discussed. Larger steady-state deformation is found for the bistable structure, compared to its mono-stable counterpart in the same flow condition. The Cauchy number is found to be the critical parameter affecting the buckling dynamics and dimensionless strain energy stored in the system. A prediction model for the dimensionless strain energy as a function of the Cauchy number is proposed. The hydrodynamic lift force generated by the fluid is found to increase the total strain energy of these bistable structures. The research could provide insight in designing morphable marine energy devices and lightweight bioinspired propulsion systems.

Aero-propulsive coupling performance and design of distributed propulsion wing

The Distributed Propulsion Wing (DPW) presents prominent advantages in terms of energy conservation during flight, but the intense integration of propulsive internal flow with aerodynamic external flow brings significant design challenges. To tackle this issue, this paper undertakes a comprehensive investigation of the aero-propulsive coupling performance of the DPW under both hovering and cruising conditions, and subsequently proposes a multi-level collaboration optimization design method based on the decomposition principle. Specifically, the complex 3D surfaces of DPW are systematically dissociated into simple 2D curves with inherent relationships for design. The decomposition is achieved based on the analysis results of the aero-propulsive coupling characteristics. And a DPW design case is conducted and subsequently analyzed in order to further validate the effectiveness and feasibility of the proposed design method. It is shown that a 115.75% drag reduction of DPW can be achieved at cruise under a specified thrust level. Furthermore, the DPW exhibits inherent characteristics of consistent lift-to-drag ratio with the thrust-drag balance constraint, regardless of variations in incoming flow velocity or total thrust.

Particle transport in open polygonal billiards: A scattering map.

Polygonal billiards exhibit a rich and complex dynamical behavior. In recent years, polygonal billiards have attracted much attention due to their application in the understanding of anomalous transport, but also at the fundamental level, due to their connections with diverse fields in mathematics. We explore this complexity and its consequences on the properties of particle transport in infinitely long channels made of the repetitions of an elementary open polygonal cell. Borrowing ideas from the Zemlyakov-Katok construction, we construct an interval exchange transformation classified by the singular directions of the discontinuities of the billiard flow over the translation surface associated with the elementary cell. From this, we derive an exact expression of a scattering map of the cell connecting the outgoing flow of trajectories with the unconstrained incoming flow. The scattering map is defined over a partition of the coordinate space, characterized by different families of trajectories. Furthermore, we obtain an analytical expression for the average speed of propagation of ballistic modes, describing with high accuracy the speed of propagation of ballistic fronts appearing in the tails of the distribution of the particle displacement. The symbolic hierarchy of the trajectories forming these ballistic fronts is also discussed.

The (UN)Importance of Inheritance

Abstract Transfers from parents—either in the form of gifts or inheritances—have received much attention as a source of inequality. This paper uses administrative data for the population of Norway to examine the share of the Total Inflows (defined as the capitalized sum of net labor income, government transfers, and gifts and inheritances received over the period) accounted for by capitalized gifts and inheritances. Consistent with other work, we find that there is much inequality in the receipt of gifts and inheritances. However, gifts and inheritances represent a small share of Total Inflows; this is true across the distribution of Total Inflows, as well as at all levels of net wealth. Gifts and inheritances are only an important source of income flows among those who have very wealthy parents. Additionally, gifts and inheritances have very little effect on the distribution of Total Inflows, suggesting that inheritance taxes may do little to mitigate inequality.

Investigation on the suitability of conventional film hole under pulsed detonation incoming flow conditions

As a novel and efficient engine, the pulse detonation engine will increasingly demand advanced cooling technology. Film cooling, widely utilized in conventional aero engines, is also anticipated to be employed in pulse detonation engines. However, further investigation is required to assess the suitability of conventional film holes for pulse detonation engines. This study determines the cooling characteristics of a plate with a single film hole in a pulse detonation engine operating at a frequency of 30Hz through numerical calculations. The types of film holes considered include cylindrical, fan-shaped, laid-back, laid-back fan-shaped, and converging-slot holes, all of which have a diameter of 1 mm and an inclination angle of 30°. The single pulse detonation period is divided into stages: initiation and detonation wave propagation, gas exhaust, and refilling. During the initiation and detonation wave propagation stage, the film hole exhibits a significant backflow phenomenon, with the magnitude of gas backflow positively correlated with the outlet area of the film hole. Notably, the converging-slot hole experiences the least amount of gas backflow, with an exit area 33 % smaller than that of cylindrical holes and a corresponding 18 % reduction in backflow enthalpy. Throughout the initiation and detonation wave propagation stage, the backflow gas carries an enthalpy ranging from 0.43 J to 0.63 J into each individual film hole. In the gas exhaust stage, the blowing ratio increases over time as the mainstream pressure decreases, leading to a rapid decline in the film cooling effectiveness of the cylindrical and laid-back holes. The converging-slot holes have the largest film covering area, thus exhibiting the highest film cooling effectiveness, which is 53 % higher than that of the cylindrical hole. In the refilling stage, the mainstream temperature reaches the same level as the secondary flow temperature, rendering the consideration of the cooling characteristics of the film hole unnecessary. Under the conditions of this study, the converging-slot hole is found to be most suitable for cooling the pulse detonation engine.

A flamelet-based Eulerian transported PDF method for the modeling and simulation of supersonic combustion

This paper presents a high-efficiency and high-fidelity approach to model supersonic combustion using the extended flamelet-generated manifold (FGM) and the Eulerian transported probability density function (PDF), also known as the Eulerian stochastic fields (ESF) method. The efficiency benefits from the FGM, where the compressibility effects induced by shock waves are considered using two extra control variables, i.e., the pressure (p) and the absolute internal energy of the oxidizer (Eox), in addition to the mixture fraction (Z) and progress variable (Yc) in traditional flamelet tables. The joint PDF for these control variables is modeled using transported PDF based on the ESF method. The ESF method enhances accuracy in the prediction of turbulence-chemistry interactions, avoiding complexity induced by the presumed PDF in the flamelet table and ad-hoc presumed and independent joint PDF assumptions, e.g., the typical presumed β-PDF for Z and δ-PDF for Yc. This FGM-ESF method is tested in large eddy simulations of two canonical hydrogen supersonic flames: a strut-stabilized hydrogen supersonic flame (DLR case) and a transverse hydrogen jet flame in a high-enthalpy incoming flow (Stanford case). For both cases, results show that including the compressibility effects in the FGM table is essential for properly describing the flame behaviors near shock waves. The sub-grid PDF of control variables significantly influences near-wall and shear-layer combustion, and the ESF method demonstrates superior performance in predicting the near-wall reaction zone and the shear-layer reaction zone compared to the perfectly micro-mixed sub-grid model (δ-PDF) for the Stanford case. This study marks the first application of the FGM-ESF approach with a Z-Yc-Eox-p FGM table to simulate supersonic flames, offering a novel perspective for future modeling efforts in this domain.Novelty and Significance StatementThe novelty of this research lies in the development and application of an efficient computational approach that for the first time couples the extended flamelet-generated manifold (FGM) method with the Eulerian stochastic fields (ESF) to simulate supersonic flames. This combined FGM-ESF method incorporates pressure and oxidizer energy as additional control variables in the FGM tabulation to account for compressibility effects. The ESF is used to describe the sub-grid scale joint probability density function without relying on complex presumed functions. Application to a canonical strut-stabilized hydrogen supersonic flame and transverse hydrogen jet flames in a high-enthalpy incoming flow demonstrate the superior predictive capabilities of the FGM-ESF method in capturing flame dynamics. The comparison between four-dimensional and two-dimensional FGM tables provides new insights into the importance of compressibility effects for these configurations.

Power and thrust control by passive pitch for tidal turbines

Tidal turbines operate in unsteady and non-uniform flows and thus experience large load fluctuations. In this study, we explore the effects of changes in freestream velocity and yaw misalignments on the performance of a turbine equipped with passively pitching blades. We compare the experimental results from a 1.2-m-diameter turbine in a recirculating open channel facility and numerical results based on blade-element-momentum theory. The thrust remains approximately constant with increasing free stream speed, meaning that the structural load on the turbine is minimised. While not held constant, the power increases at less than half of the rate of a turbine with fixed pitch blades. This finding shows that power can be controlled effectively by changing the tip speed ratio, allowing, for example, the power to be capped at a rated value by marginally increasing the angular velocity. Furthermore, the power and thrust are found to be negligibly sensitive to yawed incoming flow compared to a fixed-pitch turbine. Overall, these results demonstrate that passive pitch is a viable alternative to active pitch, and pave the way for further development of this technology.

Saturation of the compression of two interacting magnetized plasma toroids evidenced in the laboratory.

Interactions between magnetic fields advected by matter play a fundamental role in the Universe at a diverse range of scales. A crucial role these interactions play is in making turbulent fields highly anisotropic, leading to observed ordered fields. These in turn, are important evolutionary factors for all the systems within and around. Despite scant evidence, due to the difficulty in measuring even near-Earth events, the magnetic field compression factor in these interactions, measured at very varied scales, is limited to a few. However, compressing matter in which a magnetic field is embedded, results in compression up to several thousands. Here we show, using laboratory experiments and matching three-dimensional hybrid simulations, that there is indeed a very effective saturation of the compression when two independent parallel-oriented magnetic fields regions encounter one another due to plasma advection. We found that the observed saturation is linked to a build-up of the magnetic pressure, which decelerates and redirects the inflows at their encounter point, thereby stopping further compression. Moreover, the growth of an electric field, induced by the incoming flows and the magnetic field, acts in redirecting the inflows transversely, further hampering field compression.