Coriolis Force Research Articles

Coriolis force effects on the density driven estuarine circulation: Inception of a coastal current

Influence of Coriolis force on the emergence of chaos in a generalized Lorenz model of a buoyancy-driven convective system

Abstract To address complex mechanical engineering design issues, this study presents a novel optimization algorithm, the modified tornado optimizer with Coriolis forces (MTOC), which is enhanced by artificial neural networks (ANNs). To strike a balance between exploration and exploitation in high-dimensional search spaces, MTOC mimics the dynamic transformation of windstorms into tornadoes, drawing inspiration from the natural development of tornadoes influenced by Coriolis forces. The algorithm exhibits enhanced convergence behavior and optimization accuracy by incorporating ANN techniques for performance improvement and hyperparameter adjustment. Multiple mechanical component design challenges, such as those involving rolling element bearings, Ravigneaux planetary gears, Belleville springs, and helicopter hinge arms, are used to validate the efficacy of MTOC. Comparative results with existing metaheuristic algorithms show MTOC consistently outperforms others in terms of best fitness values, stability (low standard deviations), and computational efficiency, making it a powerful tool for multidisciplinary engineering optimization.

Jupiter's poles feature striking polygons of cyclones that drift westward over time, a motion governed by [Formula: see text]-drift (vortex motion caused by the latitudinal variation of the Coriolis force). This study investigates how [Formula: see text]-drift and the resulting westward motion depend on the depth of these cyclones. Counterintuitively, shallower cyclones drift more slowly, a consequence of stronger vortex stretching. By employing a 2D quasi-geostrophic model of Jupiter's polar regions, we constrain the cyclones' deformation radius, a key parameter that serves as a proxy for their vertical extent, required to replicate the observed westward drift. We then explore possible vertical structures and the static stability of the poles by solving the eigenvalue problem that links the 2D model to a 3D framework, matching the constrained deformation radius. These findings provide a foundation for interpreting upcoming Juno microwave measurements of Jupiter's north pole, offering insights into the static stability and vertical structure of the polar cyclones. Thus, by leveraging long-term motion as a constraint on vertical dynamics, this work sets the stage for advancing our understanding of the formation and evolution of Jupiter's enigmatic polar cyclones.

This study introduces a boundary element method to solve the three-dimensional problem of internal tide generation over arbitrary isolated seamounts in a uniformly stratified finite-depth fluid with background rotation, without assumptions on the size or slope of the topography. Focusing on linearly propagating waves with small tidal excursions, the approach employs a vertical mode decomposition to describe the wavefield and the wave energy flux. We apply the model to the generation of internal tides by a unidirectional barotropic tide interacting with an axisymmetric Gaussian seamount. We study the conversion rate and flow field for various topographic configurations. We qualitatively recover some of the two-dimensional results of Papoutsellis et al. (2023 J. Fluid Mech. 964 , A20), and find topographies with weak conversion rates, as discussed by Maas (2011 J. Fluid Mech. 684 , 5–24). Furthermore, our results reveal the previously underestimated influence of the Coriolis frequency on the wavefield and on the spatial distribution of radiated energy flux. Due to Coriolis effects, the energy fluxes are shifted slightly counter-clockwise in the northern hemisphere. We explain in detail how this shift increases with the magnitude of the Coriolis frequency and the topographic features and why such effects are absent in models based on the weak topography assumption.

Rotating channel flows are an important part of scientific and engineering applications including microfluidic devices, rotating machinery, and energy-efficient thermal systems. Despite extensive research, the behavior of magnetized fluids, thermal-diffusive processes and rotational effects on non-Newtonian fluids has remained underexplored. This study investigates the flow of tangent hyperbolic fluid in a vertical rotating channel under the effects of magnetic field (Lorentz force), Coriolis force, Dufour and Soret effects. The governing nonlinear differential equations are solved using MATLAB’s bvp5c solver. Results show that increasing the Grashof number from 0.5 to 1.25 enhances primary velocity by 42% which is highly relevant in designing rotating heat exchangers where natural convection aids cooling efficiency, whereas a higher Hartmann number suppresses it by 22.10% due to magnetic damping, highlights how magnetic control can be employed in MHD pumps to regulate flow rates. A 4.46% decrease in temperature was observed with an enhanced Soret effect, indicating improved thermal regulation particularly beneficial in applications like thermal insulation systems and microelectronic cooling. The entropy generation increases by 2.39% with higher values of the pressure gradient parameter, indicating greater energy loss in pressure-driven microchannel flows often encountered in cooling systems and biomedical devices. The Bejan number, skin-friction coefficient, Nusselt number and Sherwood number behavior are also analyzed. The findings provide quantitative insights relevant to designing advanced cooling systems and chemical reactors.

Abstract This study explores the complex thermo-fluid behaviour of anisotropic, fluid-saturated porous media in a rotating channel using Physics-Informed Neural Networks (PINNs). The nonlinear Darcy–Brinkman–Forchheimer equations, formulated in a rotating frame of reference, are solved directly using a mesh-free, data-efficient PINN framework. This approach enables the accurate capture of intricate multiphysics interactions that arise from the interplay of anisotropy, rotation, and viscous effects. The velocity field exhibits a primary axial component aligned with the pressure gradient and a secondary transverse component generated by Coriolis forces. Results reveal that variations in rotation rate, anisotropy, and permeability orientation significantly influence both flow and heat transfer characteristics. Axial flow rates fluctuate by up to 96%, while Nusselt numbers vary by over 30%, indicating substantial sensitivity to these parameters. Viscous dissipation contributes to asymmetric thermal behaviour across the channel walls: enhanced heat transfer occurs at the bottom wall, whereas the top wall can experience a reduction or even reversal in heat flux under certain regimes. These asymmetries are particularly pronounced in highly anisotropic configurations, where the direction-dependent permeability modulates the influence of rotational forces on the flow field. Overall, the study highlights the effectiveness of PINNs in resolving coupled, nonlinear phenomena in rotating porous systems without the need for traditional meshing. The findings provide valuable insights for the design and optimization of thermal systems in engineering applications such as geothermal energy extraction, aerospace thermal protection, and advanced cooling technologies.

Significance of Coriolis forces on the dynamics of non-Newtonian Jeffrey fluid flow under the effects of a magnetic field over a pulsating plate in a rotating frame

Automated centrifugal microfluidic platform for label-free separation and lysis of cancer cells from whole blood.

Abstract This study explores the nonlinear dynamics of ion-acoustic waves (IAWs) in a magnetized, collisional, anisotropic rotating plasma that includes hot ions, superthermal electrons, and positrons. Anisotropic ion pressure is defined using the Chew–Goldberger–Low theory. Our linear analysis shows that pressure anisotropy notably impacts wave frequency, particularly for shorter wavelengths, and identifies a threshold wavenumber beyond which wave propagation is impossible. We derive a nonlinear damped Zakharov–Kuznetsov equation by applying the reductive perturbation technique. This equation describes the phase velocity and profile of ion-acoustic solitary waves, which are significantly influenced by superthermal, electron–positron temperature ratio, pressure anisotropy, the Coriolis force, and ion collisions. Our numerical analysis reveals that IAWs propagate in the plasma in a direction parallel to the magnetic field with a phase velocity that is unaffected by the plasma rotation frequency Ω 0 {\Omega }_{0} , the magnetic field through ω c i {\omega }_{ci} , or the perpendicular pressure component P ⊥ {P}_{\perp } . The phase velocity increases with the κ \kappa index and parallel pressure P ‖ {P}_{\Vert } and decreases with the positron temperature ratio σ \sigma . Moreover, it is found that the wave amplitude decreases with increasing ion pressure ( P ‖ ) ({P}_{\Vert }) and the electron–positron temperature ratio ( σ ) (\sigma ) . On the contrary, the amplitude increases with rising superthermality κ \kappa , while collisions cause the wave amplitude to spread. The Coriolis force exclusively affects the width of electrostatic waves. The results of this study are particularly relevant for understanding wave behavior in astrophysical and space environments, especially within Earth’s magnetosphere, where nonthermal electrons and positrons coexist with anisotropic pressure ions.

Abstract. The circulation structure surrounding the Qingdao cold water mass in 2019 was investigated using three-dimensional ensembles of numerical simulations. This study reveals that a cold pool appears in early spring and reaches its peak in late May, and this pool is accompanied by local seasonal anticyclonic circulation. Momentum diagnostics reveal that vertical friction cannot be ignored because of the shallow topography and surface wind stress; as a result, the geostrophic balance is inapplicable in the Qingdao cold water mass region. Seasonal circulation mostly results from the balance of the pressure gradient, Coriolis, and vertical friction forces. The no-tide and no-wind numerical simulation results suggest that when the tidal forcing is turned off, unrealistically strong currents appear and are caused by the decrease in vertical friction in the no-tide simulation. Moreover, the direction of the eastern side of the anticyclonic circulation is reversed. Furthermore, the seasonal southwesterly monsoon contributes to the magnitude of the anticyclonic circulation, especially in the western portion of the anticyclonic circulation, by piling up the surface water eastward and further changing barotropic pressure gradient force. Additionally, upwelling occurs vertically around the Qingdao cold water mass and is influenced by tidal and wind forcings. The wind forcing affects upwelling (especially in the western part), which can be explained by Ekman pumping; the tides contribute to upwelling in the eastern part by reshaping the thermocline and further changing the barotropic and baroclinic pressure gradient force. Ensemble simulations are used, and a t test reveals that 51 % (90 %) of points, difference between the control run and the ensemble experiments without tidal forcing (and without wind forcing) is statistically significant.

As typical examples of rotational rate sensors, microelectromechanical system (MEMS) gyroscopes have been widely applied as inertial devices in various fields, including national defense, aerospace, healthcare, etc. This review systematically summarizes research advancements in MEMS gyroscope structural forms and processing technologies, which are evaluated through performance indices. The review encompasses several areas. First, it outlines the modelling principles and processes of gyroscopes on the basis of the Coriolis force and resonance, establishing a theoretical foundation for MEMS gyroscope development. Second, it introduces and analyzes the latest research advances in MEMS gyroscope structures and corresponding processing technologies. On the basis of published research advances, this review categorically discusses multidisciplinary technology properties, statistical results, the existence of errors, and compensation methods. Additionally, it identifies challenges in MEMS gyroscope technologies through classification analysis.

Mass transfer is crucial in binary evolution, yet its theoretical treatment has long relied on analytic models whose key assumptions remain debated. We present a direct and systematic evaluation of these assumptions using high-resolution 3D hydrodynamical simulations including the Coriolis force. We simulate streams overflowing from both the inner and outer Lagrangian points, quantify mass transfer rates, and compare them with analytic solutions. We introduce scaling factors, including the overfilling factor, to render the problem dimensionless. The donor-star models are simplified, with either an isentropic initial stratification and adiabatic evolution or an isothermal structure and evolution. However, the scalability of this formulation allows us to extend the results for a mass-transferring system to arbitrarily small overfilling factors for the adiabatic case. We find that the Coriolis force – often neglected in analytic models – strongly impacts the stream morphology: breaking axial symmetry, reducing the stream cross section, and shifting its origin toward the donor’s trailing side. Contrary to common assumptions, the sonic surface is not flat and does not always intersect the Lagrangian point: instead, it is concave and shifted, particularly toward the accretor’s trailing side. Despite these structural asymmetries, mass transfer rates are only mildly suppressed relative to analytic predictions and the deviation is remarkably small – within a factor of two (ten) for the inner (outer) Lagrangian point over seven orders of magnitude in mass ratio. We use our results to extend the widely used mass-transfer rate prescriptions by Ritter (1988, A&A, 202, 93) and Kolb & Ritter (1990, A&A, 236, 385), for both the inner and outer Lagrangian points. These extensions can be readily adopted in stellar evolution codes like MESA, with minimal changes where the original models are already in use.

Abstract Rotational dusty fluid flow refers to the motion of a mixture of fluid and solid particles in a rotating frame of reference. Various industrial processes, such as oil drilling, chemical processing, and materials manufacturing, have applications of rotational dusty fluid flow. Studying the dynamics of rotational dusty fluid flow is crucial for optimizing these industrial processes and improving their efficiency. The research focuses on understanding the behavior of a dusty fluid in a horizontal channel subjected to the combined influences of rotation and a magnetic field. The flow is driven by a constant pressure gradient and the movement of the upper plate, with the fluid flowing between two parallel plates. To analyze this system, a set of coupled partial differential equations governing the motion of the fluid and dust particles is developed. These equations account for both primary and secondary velocity components of the fluid and dust. To solve them, the study employs a meshfree radial basis function pseudospectral method. This advanced numerical technique is known for its flexibility in solving complex systems of partial differential equations without requiring structured grids, enabling high accuracy even in scenarios with irregular geometries or boundary conditions. The computed velocity profiles are then used to evaluate the pumping power needed to sustain flow in the absence of the pressure gradient. Results are presented through graphical analysis, showcasing the effects of key fluid parameters such as the Coriolis frequency parameter, dust particle concentration parameter, Reynolds number, Ekman number, ion slip parameter, and Hall parameter. Notably, the findings reveal that an increase in the Coriolis frequency reduces the primary velocity while increasing the secondary velocity. This behavior arises because the Coriolis force, which acts perpendicular to the flow direction, distorts the velocity profile, creating a complex interplay between rotational and flow dynamics.

The stability behaviors of rotating magnetohydrodynamic channel flows have broad relevance to various applications, particularly in microfluidic systems, such as lab-on-a-chip platforms used in engineering and biomedical devices. We extend the work [Sengupta and Ghosh, “Linear stability of a rotating channel flow subjected to a static magnetic field,” Phys. Fluids 34, 054116 (2022)] by adopting the non-modal stability approach to examine the stability of an incompressible fluid flow under the influence of spanwise system rotation and a static transverse magnetic field. Transforming the perturbed Navier–Stokes equations into the Orr–Sommerfeld framework, unlike modal analysis, we investigate short-time energy instabilities and explore the underlying mechanisms responsible for transient energy amplification by applying the Chebyshev spectral collocation method. We analyze how the non-normality of spanwise rotation controls the energy instability at low Reynolds numbers over short time intervals. At low Hartmann numbers, significant transient energy amplification occurs due to the combined effects of inertial and Coriolis forces. However, when the magnetic field becomes sufficiently strong, the transient energy growth is effectively suppressed by electromagnetic damping. The optimal initial perturbation and its corresponding response, as determined by our analysis, exhibit roll-cell structures in the form of secondary vortices, whose size progressively decreases with increasing Hartmann number. We further estimate the influence of external harmonic forcing by evaluating the resolvent norm and the numerical range associated with the modified stability operator.

Integrability and complex dynamics of solitons of a generalized perturbed KdV equation with time-dependent variable coefficients and Coriolis effect

Analysis of aerodynamic loads on vertical axis wind turbines considering the Coriolis effect

Abstract We employ a multiple-scales asymptotic analysis to derive a simple model for the mesoscale tropical atmosphere interacting with a field of cloud-scale convective circulations. Most importantly, we take account of the fact that cloud-scale convection in the tropics experiences a westward tilt under the influence of the nontraditional Coriolis force. The systematic approach uncovers a two-way coupling between the mesoscale and cloud scales and provides a physically consistent closure via the specification of averaged flux terms. This closure takes the form of a nonlocal vertical diffusion of absolute mesoscale horizontal momentum, with a diffusion kernel containing all details of the underlying convective circulations. Ultimately, it is shown that the westward tilt in convection creates upscale fluxes of momentum and drives a self-regulating vertical shear of zonal wind at the mesoscale. In the tropics where vertical shear is typically weak, the effect of the nontraditional Coriolis term (NCT) is maximized, and therefore, it has a significant effect on mesoscale dynamics. The mechanism for self-regulation uncovers an underlying tendency for the tropical atmosphere to adjust toward a state where the vertical shear of the mesoscale zonal wind balances the nontraditional component of Earth’s rotation. Ultimately, this study indicates that the NCT plays a significant role in tropical dynamics and suggests that we reassess the validity of omitting its effect in meteorological models.

Thermal instability in a two-layer nanofluid system—comprising a non-porous nanofluid layer overlying a porous nanofluid layer under the influence of the Coriolis force—is investigated in this study. The model integrates the enhanced thermal conductivity of nanofluids with rotational effects, improving heat transfer efficiency and fluid stability, making it relevant for applications in solar energy, rotating machinery, and thermal management systems. A linear stability analysis (LSA) is performed on the dimensionless momentum, energy, and nanoparticle conservation equations. The normal mode technique is applied to the perturbed equations, and the resulting eigenvalue problem is solved using the Chebyshev–Tau numerical method, implemented in MATLAB to obtain graphical results. Two configurations are examined: one with identical nanoparticles in both layers and another with different nanoparticles dispersed in the same base fluid. The effects of depth ratio, Darcy number, Taylor number, and thermal conductivity ratio on system stability are analyzed. The results reveal a bimodal stability curve, indicating complex convection modes. The system shows strong sensitivity to depth ratio and rotational effects. For identical nanoparticles, increasing the Taylor number stabilizes the system, while for aluminum–copper combinations, stability increases as the Taylor number decreases. Higher Darcy numbers delay convection, enhancing stability, whereas larger thermal conductivity ratios shift convection to the upper nanofluid layer. Unlike previous studies limited to single-layer nanofluids or microchannel flows, this work presents new insights into the coupled influence of rotation and interfacial effects, advancing the understanding of stability transitions in rotating nanofluid systems.

Abstract Marine propulsion is a significant source of noise. In this study, a hybrid method coupling computational fluid dynamics and the acoustic-analogy theory is adopted to calculate the unsteady flow field and sound field of a waterjet propulsion pump. The sound pressure level of the pump exhibits an approximately circular distribution in the radial plane and distinct dipole characteristics in the axial plane, with amplitude decreasing with increasing frequency and vessel speed. The dominant sound pressure level frequency is the blade-passing frequency, with contributions from both the rotational and guide vane passing frequencies. Among all components, the inlet channel generates the highest sound pressure level. Considering pressure pulsations, the inlet channel is dominated by the blade-passing frequency, while the frequency in the internal regions of the pump evolves from the rotational to guide-vane-passing frequency, and finally to the blade-passing frequency, with notable amplitude variations between the wall-adjacent regions and the hub. Within the impeller, zones of high enstrophy align with abrupt changes in relative velocity. The vortex evolution in blade passages is mainly driven by the relative vorticity generation and Coriolis force terms. Particularly, near the suction side of the blade leading edge, strong enstrophy fluctuations significantly intensify the flow-induced noise in the pump.