Asymmetric Regime Research Articles

Evaluation of SPARC divertor conditions in H-mode operation using SOLPS-ITER

Abstract The predicted divertor conditions for the SPARC tokamak are calculated using SOLPS-ITER for a range of scrape-off-layer (SOL) heat flux widths $\lamq$, input powers, and particle fuelling locations. Under H-mode scenario conditions with an upstream separatrix density of 1\e20 m$^{-3}$, the most conservative range of $\lamq$ extrapolations ($\approx$ 0.15 mm) results in extremely high unmitigated particle and energy fluxes to the divertor, both under full field (12.2 T) and power ($P_{SOL}$ = 29 MW) conditions, and 2/3 field with $P_{SOL}$ = 10 MW. Increasing the cross-field SOL diffusivities by 2-10x reduces the magnitude of the mitigation challenge, however strategies such as impurity seeding or strike-point-sweeping will likely still be required. 

A combination of steady-state and time-dependent SOLPS-ITER simulations are used to map out phase space diagrams of upstream and divertor conditions. At low upstream density the inner and outer divertor conditions are highly asymmetric, with a large temperature difference and significant heat fluxes driven by parallel currents. The solution has sharp bifurcations with a region of hysteresis, depending on whether the initial state is at a low or high density. This behavior is observed even when the fuelling location, cross-field diffusivity, and impurity level is changed, although the density window with asymmetry is reduced.

The addition of neon impurity seeding reduces the divertor heat fluxes, but also causes a drop in the upstream electron density with fixed particle throughput. This drop can be counteracted by increased main ion throughput, however too much neon results in a back transition into the asymmetric divertor regimes suggesting a need for control of both main ion and impurity seeding levels to achieve a desired divertor state.

Improved Electrode Performance Using Fine‐Tuned Poly(arylene piperidinium) Ionomers In Anion Exchange Membrane Fuel Cells

AbstractIonomers based on poly(arylene piperidinium)s with varying ion exchange capacities are evaluated in different combinations of anode and cathode electrodes in anion exchange membrane fuel cells. The operational conditions are chosen with an asymmetrical regime including a dry anode with 50% relative humidity at the inlet, and full humidification at the cathode. Polarization and impedance measurements are carried out in potentiostatic steps within 0.3–0.9 V and distribution of relaxation times analysis is utilized to deconvolute resistance contributions. The results show that the best cell performance is achieved with both electrodes utilizing an ionomer with the highest ion exchange capacity (IEC) of 2.79 meq g−1. Cells built exclusively from this ionomer achieved a peak power density of 1.01 W cm−2. Deconvolution of the resistance contributions revealed the impact of water content on the effective charge transfer resistance in both electrodes and a diffusion resistance associated with the movement of water from anode to cathode side. The higher conductivity and water uptake of the high IEC ionomer resulted in a reduction of both resistance contributions, leading to the highest performance under the conditions evaluated. These findings provide important insights into how to tailor the electrode layers for optimum fuel cell output.

Strongly asymmetric interactions and control regimes in the Barents Sea: a topological food web analysis

IntroductionIncreasing temperature of the global ocean alters the spatial behavior of a number of species. From the northern Atlantic Ocean, species may shift their area towards the poles. This results in the atlantification of the Barents Sea, raising questions about possible changes in species composition, community structure and community control.MethodsWe address the question whether possible changes in community control can be detected and quantified based on simple network analytical measures applied to the food web. Based on unweighted (binary) and undirected (symmetric) data, we quantify the strength of direct and indirect interactions in the network, represent the most asymmetric effects in the asymmetry graph composed of directed and weighted links and study the overlap among trophic niches of organisms.Results and discussionWe support earlier findings suggesting that the ecosystem can possibly be characterized by wasp-waist control. This would mean that focusing management efforts on intermediate trophic levels is of high importance, providing indirect benefit for organisms also at lower and higher trophic levels.

A numerical study of natural convection through a vertical heated channel with a confined circular cylinder

This study examines thermal flow structures and heat transfer through a vertical heated channel with an adiabatic circular cylinder symmetrically positioned between lateral walls. A two-dimensional numerical simulation is conducted covering a range of parameters including Rayleigh numbers Ra = 8.9 × 106–8.9 × 108, cylinder positions relative to the channel height h = 0–0.50, and blockage ratios (the ratio of cylinder diameter to channel width) β = 0.25–0.75. Three distinct flow regimes are observed at different Rayleigh numbers and blockage ratios, including steady symmetric, unsteady periodic, and unsteady asymmetric flow regimes. The steady symmetric and unsteady periodic flows are observed at all blockage ratios, while the unsteady asymmetric flow is only observed at the highest blockage ratio of β = 0.75 for Rayleigh numbers above 8.9 × 107. It is found that the presence of the cylinder significantly enhances mixing and turbulence in the channel, which in turn enhances heat transfer through the channel. A 64.3% enhancement of heat transfer is achieved at β = 0.50 and h = 0.05 for Ra = 8.9 × 108.

Late Mesozoic Tectono-stratigraphic evolution of the Hekimhan Basin and the environs (central eastern Anatolia): implications for the eastern Taurides and Gürün Curl

ABSTRACT The east-west trending Taurides form a curved area in central eastern Anatolia known as the Gürün Curl. In order to understand the origin of the Gürün Curl and Tauride evolution in general, the results of a new field study of this region have been synthesized together with previously published data. We suggest that the geodynamic evolution of the area began with the likely presence of a Tethys Ocean transform fault. This fault separated the Taurides into the Akdere Sector in the west and the Munzur Sector in the east in the Late Cretaceous. During the late Santonian–early Campanian, ophiolites obducted onto the Munzur Sector, while platform sediments continued to accumulate in the Akdere Sector. This was followed by the development of an Andean-type arc-type magmatism (the Baskil Arc) during the early–middle Campanian in the Munzur Sector. Continued closure of the Tethys led to the collision of the Bitlis Massif in the south of the Munzur Sector in the Campanian. This, in turn, resulted in continental subduction and slab roll-back that was controlled by a Subduction Transform Edge Propagator (STEP) Fault that lay on the original transform fault between the Akdere and Munzur sectors. Because the subducted slab was free at its western corner, the western edge rolled back faster than in the east, leading to an asymmetrical extensional regime on the upper plate that created the late Campanian Hekimhan Basin. While these geodynamic events were taking place in the Munzur Sector, the Akdere Sector was in a platform setting. During the Palaeocene, the Late Mesozoic units of the Akdere Sector began to overthrust on the Hekimhan Basin and the ophiolites. Following the Palaeocene, all these tectonostratigraphic units were covered by Eocene sediments around the Gürün Curl of which the modern appearance was completed by the Miocene to Recent movements along the strike-slip faults.

Derivation of Anomalous Behavior from Interacting Oscillators in the High-Temperature Regime

AbstractA microscopic model of interacting oscillators, which admits two conserved quantities, volume, and energy, is investigated. We begin with a system driven by a general nonlinear potential under high-temperature regime by taking the inverse temperature of the system asymptotically small. As a consequence, one can extract a principal part (by a simple Taylor expansion argument), which is driven by the harmonic potential, and we show that previous results for the harmonic chain are covered with generality. We consider two fluctuation fields, which are defined as a linear combination of the fluctuation fields of the two conserved quantities, volume, and energy, and we show that the fluctuations of one field converge to a solution of an additive stochastic heat equation, which corresponds to the Ornstein–Uhlenbeck process, in a weak asymmetric regime, or to a solution of the stochastic Burgers equation, in a stronger asymmetric regime. On the other hand, the fluctuations of the other field cross from an additive stochastic heat equation to a fractional diffusion equation given by a skewed Lévy process.

Vietnamese Entrepreneurs in Russia: Immigration, Business Problems and Cooperation Prospects

The paper analyzes some features of Vietnamese immigration to the Russian Federation. We provide estimates of the number of Vietnamese citizens living in Russia, their distribution by region, and key areas of employment. The results obtained in the work are based on official data published by Rosstat, the Main Directorate for Migration of the Ministry of Internal Affairs of Russia, as well as some survey data conducted by the authors of the article. We can say that despite the existence of an agreement on a “comprehensive strategic partnership” between Russia and Vietnam, the potential of Vietnamese migration remains underestimated. The structure of migration flows from Vietnam to Russia is dominated by labor and educational migration. However, in recent years Russia has lost some of its advantages, which were formed during the Soviet Union. Vietnamese migrants find new directions for migration. Among them are the countries of ASEAN, the USA, the countries of Europe. The main barriers to realizing Vietnam's migration potential in relation to Russia are the maintenance of an asymmetric visa regime, a decrease in the competitiveness of Russian wages, and high bureaucratic barriers to the entry of Vietnamese businesses into Russian regions. Additional risk factors are geopolitical tensions and the volatility of the ruble exchange rate. Nevertheless, it is noted that there is still interest from Vietnamese entrepreneurs to open a business in Russia. Opportunities for expanding Russian-Vietnamese migration ties may lie in the plane of the implementation of the Free Trade Agreement between the EAEU and Vietnam, ratified in October 2016.

Convergence and persistent contrasts in the determinants of working-age women in Sweden and Japan living alone since the 1990s

The increase in one-person households (OPHs) in the developed world is often seen as the result of a trend in which individualistic values and behaviors are replacing family solidarity. Nordic countries have been identified as frontrunners in this development. In Asia, equally developed countries like Japan retain elements of a strong-family system and an asymmetrical gender regime, simultaneously as they are experiencing rapid increases in OPHs. This article aims to uncover how the demographic and socioeconomic composition of OPHs have developed since the 1990s among working-age women in Sweden and Japan. Our results show that, in particular, civil status and income play different roles for OPH-living in Sweden and Japan. In contrast to Japan, the level of OPHs remained stable over time in Sweden, and even declined among women with high incomes. This suggests that the negative association between family formation and women’s economic activity is temporary and only prevails as long as society has not adapted to the convergence of men’s and women’s socioeconomic roles. The findings are discussed in light of the “second demographic transition” and “dual equilibrium theory”.

Effects of aspect ratio and initial pressure on asymmetric flame and flame instability of premixed CO/air

Syngas is a promising alternative energy carrier with low carbon and pollutants emissions, and CO is the main component. The combustion characteristics of stoichiometric CO/air mixtures with varied initial pressure (0.5–1.5 atm) and aspect ratio (12–40) were examined through experiments in a rectangular closed duct. This experiment simulated the transport and storage conditions of CO to study its combustion characteristics at different aspect ratios and initial pressures. The flame images and overpressure dynamics were captured by high-speed camera and pressure sensor, respectively. Experiment results proved that the increase in aspect ratio had an important effect on flame shape evolution. The tilted flame for low aspect ratios was affected by buoyancy, while flames with high aspect ratios were influenced by competing buoyancy and intrinsic instability. The results showed that the flame morphology and dynamics were enhanced with increasing aspect ratio and initial pressure. The intrinsic instability of premixed CO/air combustion was investigated, and the formation mechanism of tilted flame and twisted flame were comprehensively analyzed. Qualitative distinctions were made between symmetric and asymmetric flame morphology regimes.

Studying the Oscillating Flow around Unconfined Obstacle of Elliptical Cross-Section

The present paper focuses on the effect of geometric shape of a cylindrical body submerged in an oscillating flow by means of numerical investigations. The cylindrical body has an elliptic cross-section with a variation of its elliptic ratio (ratio between major and minor axes of the elliptic section). The flow direction is oriented along the major axis. Three regimes from (Tatstuno and Bearman) maps are studied namely, a symmetric regime A and two other asymmetric regimes D and F. The flow field structures, the Morison coefficients of longitudinal forces and the root mean square (r.m.s.) of transverse forces are computed with respect to the elliptic ratio variation. For the case of cylinders with slightly elliptic cross-section, vortices and pressure fields are very similar to those of a circular cylinder. For the case of regime A, the vortex shedding is always symmetric despite the unbreakable variation of the elliptic ratio. On the other hand, the reduction of the elliptic ratio weakens the asymmetry of the flow for regimes D and F. Moreover, the flow in each regime becomes completely symmetric at a given value of the elliptic ratio. In fact, the predicted longitudinal component of the force acting on the cylinder decreases with the reduction of this ratio. This results in the same manner on the behavior of Morison coefficients. With regard to the symmetric regime A, the transverse force does not manifest itself for all considered ratios. On the other hand, the transverse force in the case of asymmetric regimes decreases rapidly with increasing the ellipticity of the cylinder. The present study showed us that the inertia coefficient is sensitive to the vortex path; however, the drag coefficient is independent of the vortex path. Both coefficients depend simultaneously on Reynolds number and the geometric shape of the body.

Theoretical Study of Phase Behaviors of Symmetric Linear B1A1B2A2B3 Pentablock Copolymer.

The nanostructures that are self-assembled from block copolymer systems have attracted interest. Generally, it is believed that the dominating stable spherical phase is body-centered cubic (BCC) in linear AB-type block copolymer systems. The question of how to obtain spherical phases with other arrangements, such as the face-centered cubic (FCC) phase, has become a very interesting scientific problem. In this work, the phase behaviors of a symmetric linear B1A1B2A2B3 (fA1 = fA2, fB1 = fB3) pentablock copolymer are studied using the self-consistent field theory (SCFT), from which the influence of the relative length of the bridging B2-block on the formation of ordered nanostructures is revealed. By calculating the free energy of the candidate ordered phases, we determine that the stability regime of the BCC phase can be replaced by the FCC phase completely by tuning the length ratio of the middle bridging B2-block, demonstrating the key role of B2-block in stabilizing the spherical packing phase. More interestingly, the unusual phase transitions between the BCC and FCC spherical phases, i.e., BCC → FCC → BCC → FCC → BCC, are observed as the length of the bridging B2-block increases. Even though the topology of the phase diagrams is less affected, the phase windows of the several ordered nanostructures are dramatically changed. Specifically, the changing of the bridging B2-block can significantly adjust the asymmetrical phase regime of the Fddd network phase.

Coupling performance of two tandem and side-by-side inverted piezoelectric flags in an oscillating flow

The flow-induced vibration characteristics and energy extraction performance of two flexible inverted piezoelectric flags arranged in tandem and side-by-side configurations in an oscillating flow are studied. An immersed boundary-lattice Boltzmann method is employed for Reynolds number of 100, mass ratio of 2.9 and non-dimensional bending stiffness of 0.26 which correspond to the maximum flapping amplitude for a single inverted flag in a uniform flow. 2D simulations are conducted by varying the ratio R of the frequency of the oscillating flow to the fundamental natural frequency of the flag and the horizontal velocity amplitude (Au) of the flow. Three coupling regimes at Au=0.5 are identified for both tandem and side-by-side flags: chaotic oscillations regime I (0.1≤R≤1), large periodic and symmetric oscillation regime IIa1.1≤R≤1.5andIIb(2.1≤R≤3.0), and small periodic and asymmetric oscillation regime III(1.6≤R≤2). The maximum mean electrical power coefficient C¯P occurs in regime IIa at R=1.5 with, α (piezo-mechanical coupling parameter) = 0.5, and β (piezo-electric tuning parameter) = 1.5. C¯P is 0.1 for a tandem upstream flag, 0.068 for the tandem downstream flag and 0.1 for both side-by-side flags, and is respectively 120%, 300% and 213%, higher than that of the corresponding flag in the uniform flow. This improvement is attributed to the higher flapping angular amplitude (180°), the higher ratio of the flapping frequency of the flags to the oscillating frequency of the flow (virtually constant at 0.5), and constructive vortex interaction in regime IIa.

Synergistic analysis of wake effect of two cylinders on energy harvesting characteristics of piezoelectric flag

In this study, the effect of asymmetric wake flow regime of two side-by-side cylindrical bluff bodies on power output is experimentally examined by using a piezoelectric flag. Different synchronization modes of the flag with wake flow are observed. It is demonstrated that the streamwise gap between the flag and cylinders (Gx), and the center-to-center gap between cylinders have a significant impact on the flag's dynamical behavior that results in a fluctuation in the power output of the piezoelectric flag. The levels of output power are analyzed by varying the Gx and the cross-stream or lateral gap (N/d) between the two cylinders. N/d values from 1.0 to 2.0 for different values of Gx (2.0 ≤ Gx ≤ 4.0) are experimentally tested. The comparison of the flapping response at each point is made to ascertain the impact of the harvester's dynamic behavior on the output energy. The power generated at each point is recorded for all cases and a comparative analysis is made to find the optimal configuration. Limited research is conducted in the past to enhance the energy output by using the bluff body with the improved wake dynamics. Hence, two cylinders are employed in a uniform flow and crosswise gap between cylinders is varied to change the characteristics of the wake region. The cylinder arrangement with N/d = 1.0, shows continuous oscillations and higher output power persisting for 2.0 ≤ Gx ≤ 4.0. The monotonic rise in power output is observed till Gx = 4.0. The stated configurations with N/d = 1.0 gives a significant advantage over a single-cylinder-based energy harvester as a kinetic source of fluid energy harvester from the flowing fluid. The output power became almost doubled with an increase of 95% approximately using side-by-side arrangement.

Energy harvesting of inverted piezoelectric flags in an oscillating flow

The energy harvesting potential of flexible structures (e.g. flags) made of piezoelectric materials has drawn rapidly increasing attention in recent years. In this work, we numerically study the energy harvesting performance of an inverted piezoelectric flag in an oscillating flow using an immersed boundary-lattice Boltzmann method for Reynolds number of 100, mass ratio of 2.9 and non-dimensional bending stiffness of 0.26 which correspond to the maximum flapping amplitude for a single inverted flag in a uniform flow. 2D simulations are conducted by varying the ellipticity (e), the ratio R of the frequency of the oscillating flow to the fundamental natural frequency of the flag and the horizontal velocity amplitude (Au) of the flow. Three coupling regimes at Au=0.5 are identified: chaotic oscillations regime I (0.1≤R≤1 ), large periodic and symmetric oscillation regime IIa1.1≤R≤1.5and IIb(2.1≤R≤3.0), and small periodic and asymmetric oscillation regime III(1.6≤R≤2). The maximum mean electrical power coefficient C¯P occurs in regime IIa at R=1.5 with Au=0.5, α (piezo-mechanical coupling parameter) = 0.5, and β (piezo-electric tuning parameter) = 1.5. C¯P is 0.10 for a single inverted flag, and is 148%, higher than that of the corresponding flag in the uniform flow. This improvement is attributed to the higher flapping angular amplitude (180°), higher ratio of the flapping frequency to the oscillating frequency (virtually constant at 0.5) of the flags, and constructive vortex interaction in regime IIa.

Witnessing entanglement between two two-level atoms moving inside a leaky cavity under classical control

Based on the quantum memory-assisted entropic uncertainty relation (QMA-EUR), we investigate the Markovian and non-Markovian dynamics of entanglement witness in a two-atom system that asymmetrically are coupled to a leaky cavity with two-photon relaxation. The atoms are two-level systems, they move inside the cavity and interact with a classical driving laser field. We discuss in detail the effects of the translational movement of the atoms, classical driving field and atom-cavity coupling on the protection of entanglement witness. Our results show that with a regular increase in the intensity of the classical driving field, the entanglement region witnessed by lower bound of QMA-EUR increases and the time of entanglement witness gets longer. In the Markovian regime, we find that quantum entanglement between the moving atoms can be witnessed for a longer time by increasing the velocity of the atoms. However, in the non-Markovian regime, higher speeds are required to witness entanglement over long time intervals. In addition, we conclude that the entanglement region witnessed by the lower bound of QMA-EUR can be protected in both the symmetrical and asymmetrical atom-cavity coupling regimes. In the asymmetrical regime, a better protection can be achieved when the memory atom is coupled to the cavity field stronger than the other atom.

Journeys of Violence: Trajectories of (Im-)Mobility and Migrants’ Encounters with Violence in European Border Spaces

On their journeys to and through Europe, refugees and other migrants are commonly subjected to violence in its multifaceted forms. We argue that these “journeys of violence” are a direct effect of a fundamentally uneven and asymmetric global mobility regime that creates frictions and fragmentations in the European border space and beyond. Our argument is based on: (1) a state-of-the-art literature review on refugees’ mobilities towards Europe and new patterns of involuntary immobilisation through border regimes, (2) a secondary analysis of recent quantitative data from the Socio-Economic Panel (SOEP), which includes a large data set on refugee’s journeys to Germany, and (3) original qualitative interviews that were conducted with migrants in Germany and Bosnia-Herzegovina. We will first show that mobility in the context of violence is highly selective and that trajectories of mobility significantly depend on mobility capital. Second, we consider the fortification of European borders and the externalisation of control regimes as facets of structural violence and demonstrate their effects on refugees’ mobility, namely the fragmentation of journeys and the systemic production of situations of protracted immobility at multiple border sites. Third, we provide insights into refugees’ exposure to and experiences of direct violence on their journeys, which must be understood as immediate consequences of the structurally violent conditions that govern their mobility and the cultural violence of delegitimising and illegalising refugees’ movements.
 * This article belongs to a special issue on "Refugee Migration to Europe – Challenges and Potentials for Cities and Regions".

Dynamics of droplet impact on a superhydrophobic disk

An experimental study is performed to investigate the effect of tangential velocity on the dynamics of a water droplet impacting on a spinning superhydrophobic surface. It is revealed that an increase in the tangential velocity results in the spreading of a droplet from symmetrical to asymmetrical shape on the superhydrophobic surface. Moreover, depending on the impact and tangential velocities, three behaviors are observed: bouncing, symmetrical splashing, and asymmetrical splashing. In the bouncing regime, it is found that the droplet contact time is independent of impact velocity and decreases as the tangential velocity increases. However, the maximum spreading diameter in this regime is a function of both the impact and the tangential velocities. Furthermore, a splashing threshold defined as WeRe1/21−kRe−1/2V/U2=K is introduced to estimate the transition between the bouncing, symmetrical splashing, and asymmetrical splashing regimes. It is revealed that the value of K in the present work (i.e., superhydrophobic spinning disk) is approximately 60% less than the K value obtained by other researchers for the case of aluminum spinning disk. Moreover, two values are found for k to define the boundaries between these three observed regimes.

Wind Forces and Flow Patterns of Three Tandem Prisms with a Small Height–Width Ratio

Wind tunnel tests and large eddy simulations were conducted to investigate the dependency of wind forces and flow patterns on the spacing (S) for three tandem prisms with a small height–width ratio H/W = 0.4. At the spacing ratio S/W = 0.7, mean and root-mean-square drag of downstream prisms have large local peaks, and their magnitudes are larger than those at adjacent spacing ratios; these should be noted to ensure the safety and economy of the wind-resistant design of prism-like low-rise buildings. These phenomena are different from that of a small group of tandem prisms with a large H/W and a large group of tandem prisms with a small H/W. At S/W = 0.7, tap pressure time histories of downstream prisms are non-stationary with abrupt changes, but wind force time histories of downstream prisms are stationary, unlike a small group of tandem prisms with a large H/W, where both tap pressure and win d force time histories are non-stationary. Above phenomena at S/W = 0.7 are attributed to a special asymmetric time-averaged wake regime, which has two modes with symmetric wake flow directions and they irregularly switch. The duration of each mode is ruleless. This special wake regime was not observed in previous studies on tandem prisms.

Mixing Improvement in a T-Shaped Micro-Junction through Small Rectangular Cavities.

The T-shaped micro-junction is among the most used geometry in microfluidic applications, and many design modifications of the channel walls have been proposed to enhance mixing. In this work, we investigate through numerical simulations the introduction of one pair of small rectangular cavities in the lateral walls of the mixing channel just downstream of the confluence region. The aim is to preserve the simple geometry that has contributed to spread the practical use of the T-shaped micro-junction while suggesting a modification that should, in principle, work jointly with the vortical structures present in the mixing channel, further enhancing their efficiency in mixing without significant additional pressure drops. The performance is analyzed in the different flow regimes occurring by increasing the Reynolds number. The cavities are effective in the two highly-mixed flow regimes, viz., the steady engulfment and the periodic asymmetric regimes. This presence does not interfere with the formation of the vortical structures that promote mixing by convection in these two regimes, but it further enhances the mixing of the inlet streams in the near-wall region of the mixing channel without any additional cost, leading to better performance than the classical configuration.

Effects of flow unsteadiness and chemical kinetics on the reaction yield in a T-microreactor

Experimental flow visualizations and velocity measurements are used jointly with numerical simulations to investigate the mixing and monitor the reaction progress in the periodic flow regimes occurring in a T-shaped microreactor. We considered the effects of different kinetic constants, with very different characteristic chemical time scales resulting in a wide range of Damköhler numbers.A remarkable agreement between experiments and simulations is found both in terms of flow pattern and reaction progress. Two different flow regimes are present for increasing Reynolds number. The first is the periodic asymmetric regime, characterized by the shedding of vorticity-blobs along the mixing channel leading to a further increase of the mixing performance compared to the steady engulfment regime. The second regime is the periodic asymmetric one, which is mainly a poorly mixed segregated regime with periodic oscillation at the interface between the two reactants. The mixing degree significantly increases in the unsteady asymmetric regime, whereas it predictably drops down in the unsteady symmetric regime. In the periodic asymmetric regime the reaction yield follows the same function of the Damköhler number, describing the residence to chemical time-scale ratio, and of a non-dimensional kinetic constant, taking into account also fluid properties, previously proposed for the steady vortex and engulfment regimes. In the periodic symmetric regime, the reaction yield is found to depend only on the Damköhler number, with the same dependence previously highlighted for the steady segregated regime.