Velocity Vector Research Articles

Numerical Study on the Mechanism of Gas Explosion Suppression by Different Arrangement Forms of Staggered Cylinders

ABSTRACT In order to study the suppression mechanism of porous media on gas explosion, the gas explosion behavior in a pipeline with one end closed and the other end temporarily closed by a thin film was numerically simulated in this paper, in which the porous media structure was characterized by “pseudo-porous media” composed of staggered cylinders. The RANS method is used to simulate turbulence in numerical calculation, and the coupling effect between turbulence and combustion is described by the reaction progress variable equation. The calculation results show that, compared with porosity, hole spacing is a more critical parameter affecting gas explosion. The function of pores is mainly reflected in the initial stage of explosion flame development, and the function of pore spacing is reflected after the flame reaches the maximum instantaneous displacement velocity. When the Pe number calculated based on local aperture and laminar flame velocity is less than 72, the flame cannot pass through porous media, and the influence of porous media on gas explosion can be shown. When the Pe number is greater than this value, the influence of porous media on gas explosion is not obvious; The hole spacing has a significant effect on the flame shape, bifurcation number, and flame thickness. When the hole spacing is larger, the flame front is more slender and bifurcated, while when the hole spacing is smaller, the flame presents a more blunt shape, and its expansion is delayed to a greater extent. This law provides a strong basis for the optimization of porous media in burner design, especially in adjusting the flame shape and improving combustion efficiency.

Underwater DVL Optimization Network (UDON): A Learning-Based DVL Velocity Optimizing Method for Underwater Navigation

As the exploration of marine resources continues to deepen, the utilization of Autonomous Underwater Vehicles (AUVs) for conducting marine resource surveys and underwater environmental mapping has become a common practice. In order to successfully accomplish exploration missions, AUVs require high-precision underwater navigation information as support. A Strapdown Inertial Navigation System (SINS) can provide AUVs with accurate attitude and heading information, while a Doppler Velocity Log (DVL) is capable of measuring the velocity vector of the AUVs. Therefore, the integrated SINS/DVL navigation system can furnish the necessary navigational information required by an AUV. In response to the issue of DVL being susceptible to external environmental interference, leading to reduced measurement accuracy, this paper proposes an end-to-end deep-learning approach to enhance the accuracy of DVL velocity vector measurements. The utilization of the raw measurement data from an Inertial Measurement Unit (IMU), which includes gyroscopes and accelerometers, to assist the DVL in velocity vector estimation and to refine it towards the Global Positioning System (GPS) velocity vector, compensates for the external environmental interference affecting the DVL, therefore enhancing the navigation accuracy. To evaluate the proposed method, we conducted lake experiments using SINS and DVL equipment, from which the collected data were organized into a dataset for training and assessing the model. The research results show that the DVL vector predicted by our model can achieve a maximum improvement of 69.26% in terms of root mean square error and a maximum improvement of 78.62% in terms of relative trajectory error.

High-resolution hemodynamic estimation from ultrafast ultrasound image velocimetry using a physics-informed neural network

Objective.Estimating the high-resolution (HR) blood flow velocity and pressure fields for the diagnosis and treatment of vascular diseases remains challenging.Approach. In this study, a physics-informed neural network (PINN) with a refined mapping capability was combined with ultrafast ultrasound image velocimetry (u-UIV) to predict HR hemodynamic parameters. Specifically, the Navier-Stokes equations were encoded into the PINN to dynamically optimize the network performance under physical constraints, and a refined mapping network was added at the input to achieve data refinement. During the prediction of HR ultrasound hemodynamic parameters, only the sparse spatial coordinates in the time series were input into the PINN, and the velocity vectors generated from the u-UIV were used together with physical residuals to enhance the physical correctness of HR predictions during the iterative process.Main results.The performance of the refined mapping network was validated via simulations, with a 1.9-fold increase in the radial resolution and a 2.5-fold increase in the axial resolution. HR velocity field estimation fromin vitroandin vivodata showed good agreement with theoretical values and u-UIV measurements, with micrometer-level spatial resolution (88µm×115µm for straight vessel, 75µm×120µm for stenotic vessel and 63µm × 79µm forin vivodata), while the pressure field could be inferred from physical laws.Significance.The proposed method performs well when few data samples are available and has the potential to assist in the clinical diagnosis of vascular diseases.

Gas explosion overpressure loads in utility tunnels under different pipe support spacing

To investigate the effects of pipe support system characteristics on gas explosion overpressure loads in utility tunnel gas compartments, a 200 m × 2 m × 3 m model of a typical Chinese utility tunnel was constructed using CFD dynamics. Analysis of spatial and temporal distributions of explosion overpressure load under different support spacings. The results indicated that a short support spacing (L = 5 m) contributes to a more uniform distribution of the gas cloud and enhanced the average flame propagation velocity, whereas a medium support spacing (L = 15 m, 25 m) significantly increased the peak overpressure and instantaneous flame velocity. The explosion overpressure curve showed a multipeak structure, with peak P1 caused by the precursor shock wave and peaks P2–P4 caused by the reflected wave. Within 70 m, the secondary reflected wave P3 dominated, and within 130–200 m, the first reflected wave, P2, played a major role. The peak overpressure loads at different support spacings decreased and subsequently increased along the length of the utility tunnel, and the maximum peak overpressure load was reached at the end. The peak overpressure in the same cross-section is unevenly distributed; the closer to the far-end wall, the more significant the difference, and the maximum overpressure usually appears near the top of the tunnel. According to the quantitative relationship between the peak explosion overpressure and support spacing, the optimised design of the pipe support spacing should not be less than 25 m.

CFD study on the effect of the baffles geometry in sedimentation efficiency in wastewater treatments through Large Eddy Simulations

Sedimentation tanks represent one of the most important components of any water and wastewater treatment plants. The lack of knowledge of hydraulics in sedimentation tank leads to unnecessary capital and operating costs as well as water pollution in the form of excessive sludge. Improper and inadequate design cause overloading of filters, and lead to frequent backwashing, which in turn waste a significant percentage of treated water. Sedimentation tanks require a uniform flow field to ensure the correct operating conditions. Unfortunately, the development of circulation zones causes deep deviation from the uniformity, bringing negative effects on the efficiency of the tank. The focus of this study is to apply Computational Fluid Dynamics (CFD) to study and to improve the sedimentation efficiency through the optimization of the hydrodynamics inside settling tanks. In the present analysis, Large Eddy Simulation (LES) is used to simulate three-dimensional turbulent flow and scalar tracer transport in different settlers using a structured finite-volume discretization. The results show how the baffles’ geometry, as well as the inlet design, influences the retention time distribution of the tank, varying the sedimentation efficiency. In particular, the increase of baffles inside the tank reduces the free space and allows a more uniform distribution of velocity vectors. This reduces both short circuits and recirculation zones bringing the flow closer to the ideal condition. On the other hand, the inlet position influences the velocity on the tank’s bottom, with possible particles re-suspension effects.

Three-dimensional Modeling of the Interaction of a Bubble pair with a Rigid Wall using Boundary Integral Method

This study examines the three-dimensional dynamics of two gas bubbles near a horizontal rigid wall, focusing on how inter-bubble distance affects their shape, size, and jet formation. The Boundary Integral Method (BIM) with a novel local smoothing technique is employed. Critical parameters including jet velocity, bubble centroid movement, bubble radius, and collapse time are computed for each bubble to understand their interaction dynamics comprehensively. The velocity vector field and pressure distribution surrounding the bubbles are analyzed, providing detailed insights into the fluid dynamics. The findings demonstrate that inter-bubble distance significantly influences their interaction and overall behavior. These results advance the understanding of bubble dynamics near rigid boundaries, with potential applications across various scientific and engineering disciplines.

Research on the possibility of carrying out convoy driving missions using vehicles with varying degrees of autonomy

The objective of this work is to assess the possibility of driving unmanned vehicles in a convoy, depending on the vehicle type (wheeled or tracked, level 0, according to SAE J3016), and the mutual coincidence with a human-controlled vehicle in accordance with the driving scenario adopted. The assessment is based on tests carried out while driving the vehicles along a designated route and measuring the physical quantities that describe the vehicles’ motion, such as the components of the velocity vectors and distances between the vehicles. The tests were carried out on a safe training ground, using inertial-satellite devices mounted on the vehicles; they provide a good basis for planning the minimum passage corridor for a column of vehicles. During the tests, the expected distances between the vehicles were recorded and analyzed depending on the above-mentioned types of the vehicles; based on that, the possibility of using the technology in the carrying out of various missions for the needs of the tactical level units of the Polish Armed Forces was preliminarily assessed. The required lane width for the safe passage of Target 1, Hunter and Target 2 vehicles along the designated routes was calculated, taking into account the external dimensions of the vehicles, the additional widths associated with the vehicles' yaw angles and the maximum lateral distances between the vehicles. During tests of a convoy of remote-controlled vehicles, maintaining a speed of 1.5 m/s and a distance of 10 m, the requirements for the lane width for safe passage were analyzed. The largest lateral gaps were observed between Target 2 and Hunter vehicles, which may affect the planning of the convoy route. The differences in lane width between the two tests were due to the yaw angles of the vehicles and their different dimensions and drive types. In the first test, the lane width for Target 1 and Hunter was 5.50 m and for Target 2 3.70 m; in the second test it was reduced to 3.73 m and increased to 3.75 m, respectively.

Mathematical Modeling of Velocity Field Induced by the Vortex

In new technological applications, it is important to use vortex distributions in the area for obtaining large velocity fields. Analogous to electromagnetic and fluid mechanics inductions, vortices are described by the same relationship: the Biot-Savart law. When vortex threads form a vortex track due to fluid mechanics, they induce, analogous to electrical coils on an iron core, a core flow that can be faster than the wind that generates it. In this publication, the velocity field induced in a cylinder using the axially symmetric system of vortex rings and screw vortices and the hydrodynamic flow function in the ideal incompressible fluid are calculated. Also similar problem for mathematical modelling of the heat generation in fluids with alternating current using vortexes is considered. In this paper, it was calculated the distribution of the velocity field and distribution of stream function for ideal incompressible fluid, induced by a different system of finite number of vortex threads: (1) circular vortex lines in a finite cylinder, positioned on its inner, (2) spiral vortex threads, positioned on the inner surface of the finite cylinder or cone, (3) linear vortex lines in the plane channel, positioned on its boundary. An original method was used to calculate the components of the velocity vectors. Such kind of procedure allows calculating the velocity fields inside the domain depending on the arrangement, the intensity, and the radii of vortex lines. In this paper, we have developed a mathematical model for the process in the element of Hurricane Energy Transformer. This element is a central figure in the so-called RKA (ReaktionsKraftAnlage) used on the cars' roofs.

Role of Intraplate Strike-Slip Earthquakes in Accommodating Convergence Across the Eastern Himalayan Plate Boundary System

Abstract North-East India, at the eastern extremity of the Himalaya, is one of the most rapidly deforming intraplate regions. The tectonics of this region is shaped by oblique convergence between two nearly perpendicular plate boundaries of the Eastern Himalaya and the Indo-Burman convergence zone. This region of distributed deformation is associated with intraplate strike-slip and oblique-slip earthquakes. We model the source mechanisms of six recent moderate-to-strong intraplate earthquakes (5.0≤ Mw ≤6.7) using teleseismic P- and SH-waveform inversion and use source directivity and rupture back-projection, for the largest event, to isolate the fault plane. We combine these mechanisms with previous earthquake source studies, GPS-geodetic-velocity vectors, and GPS-derived strain-rate field, to build a kinematic model. Majority of the earthquakes have strike-slip to oblique-slip (thrust) motion and originate in the middle-to-lower crust. These reveal that the entire NE-Indian crust is seismogenic. The oblique-thrust earthquakes occur due to high in-plane compressive stresses in the flexed Indian Plate. The region north of the Dawki Fault, in the vicinity of the Kopili and Dhubri-Chungthang Fault Zones, deforms through dextral strike-slip faulting and anticlockwise rotation of blocks along NW-SE trending transverse structures. The transitional crust of the Bengal Basin has several NE-SW trending paleo-rifts which are reactivated as sinistral strike-slip faults and the intervening blocks undergo clockwise rotation. The oblique convergence between the Indian and Eurasian Plates is partitioned into dextral and sinistral strike-slip motions across NE-India. The GPS velocity vectors and the strain-rate field indicate that the region north of the Dawki Fault has strong coupling between the surface deformation and the earthquake faulting. However, in the region south of the Dawki Fault, the coupling is weaker. The strike-slip earthquakes beneath Indo-Burma probably occur due to a complex interplay between the trench-normal slab-pull forces and lateral-shear forces set up by the strike-parallel components of the interplate-coupling resistance and the mantle-drag forces.

Mapping River Flow from Thermal Images in Approximately Real Time: Proof of Concept on the Sacramento River, California, USA

Image velocimetry has become an effective method of mapping flow conditions in rivers, but this analysis is typically performed in a post-processing mode after data collection is complete. In this study, we evaluated the potential to infer flow velocities in approximately real time as thermal images are being acquired from an uncrewed aircraft system (UAS). The sensitivity of thermal image velocimetry to environmental conditions was quantified by conducting 20 flights over four days and assessing the accuracy of image-derived velocity estimates via comparison to direct field measurements made with an acoustic Doppler current profiler (ADCP). This analysis indicated that velocity mapping was most reliable when the air was cooler than the water. We also introduced a workflow for River Velocity Measurement in Approximately Real Time (RiVMART) that involved transferring brief image sequences from the UAS to a ground station as distinct data packets. The resulting velocity fields were as accurate as those generated via post-processing. A new particle image velocimetry (PIV) algorithm based on staggered image sequences increased the number of image pairs available for a given image sequence duration and slightly improved accuracy relative to a standard PIV implementation. Direct, automated geo-referencing of image-derived velocity vectors based on information on the position and orientation of the UAS acquired during flight led to poor alignment with vectors that were geo-referenced manually by selecting ground control points from an orthophoto. This initial proof-of-concept investigation suggests that our workflow could enable highly efficient characterization of flow fields in rivers and might help support applications that require rapid response to changing conditions.

Two-dimensionally controllable untethered swimmer using a T-shaped antenna structure with an electrical discharge in air and water

Abstract Untethered microswimmers that can move freely on the water surface are important for next-generation microfabrication. Here, we propose an untethered swimmer and its navigation method using electrical discharge in air and water. Specifically, we demonstrate that a swimmer with a T-shaped antenna structure can move in the left or right directions according to the high-voltage pulse application between the underwater and aerial electrodes. Furthermore, we demonstrate that a swimmer with a modified T-shaped antenna structure can be controlled on the two-dimensional water surface freely using a four-external aerial electrode system. In addition, by the observation with a high-speed camera (960 fps), we found that the expansion of bubbles generated by the underwater electric discharge near the side antenna terminal of the swimmer propelled the swimmer with the instantaneous maximum initial velocity of $\sim$300 mm/s. Our findings should contribute to the next-generation microfabrication on the water surface.

Exact Solutions to the Oberbeck–Boussinesq Equations for Describing Three-Dimensional Flows of Micropolar Liquids

The article proposes several classes of exact solutions to the Oberbeck–Boussinesq equations to describe convective flows of micropolar fluids. The possibility of using families of exact solutions for convective flows of classical incompressible fluids to micropolar incompressible fluids is discussed. It is shown that the three-dimensional Oberbeck–Boussinesq equation for describing steady and unsteady flows of micropolar fluids satisfies the class of Lin–Sidorov–Aristov exact solutions. The Lin–Sidorov–Aristov ansatz is characterized by a velocity field with a linear dependence on two spatial coordinates. These coordinates are called horizontal or longitudinal. The coefficients of the linear forms of the velocity field depend on the third coordinate (vertical or transverse) and time. The pressure field and the temperature field are described using quadratic forms. Generalizations of the Ostroumov–Birikh class are considered a special case of the Lin–Sidorov–Aristov family for describing unidirectional flows and homogeneous shear flows. An overdetermined system of Oberbeck–Boussinesq equations is investigated for describing non-homogeneous shear flows of non-trivial complex topology in 3D metric space. A compatibility condition is obtained in the Lin–Sidorov–Aristov class. Finally, a class of exact solutions with a vector velocity field that is nonlinear in part of the coordinates is presented in our analysis; such partially invariant solutions correspond to theoretical findings regarding symmetric/asymmetric properties of flow fields in solutions topology in a part of the existence appropriate for symmetry for the obtained invariant solutions.

Analytical Modeling of Effluent Discharges Spreading by Tidal Oscillation Currents on a Sloping Beach

ABSTRACTAn analytical solution of the two‐dimensional advection–diffusion equation is introduced that models the spreading of effluent discharges into coastal waters affected by tidal oscillation currents on a sloping beach. It is assumed that the advection part may be expressed as a vector of fluid velocity with two components. The first component presents the longshore flow, in the direction, by a simple tidal oscillation model. The weaker second component, in the direction, reflects the cross‐shore depth‐variation velocity. By separating the variables, the equation in two dimensions is reduced to the product of two time‐dependent equations in one dimension that can be solved analytically. Some analysis and graphical plotting with discussion related to the product solution are given. Comparisons with an available analytical solution for a steady‐state case and numerical simulations are also addressed.

Theoretical and computational studies of Rayleigh-Bénard convection in liquid gallium with stress-free boundaries

The nonlinear analysis using the finite volume method is carried in a thin rectangular domain filled with liquid gallium having stress-free horizontal isothermal boundaries for stationary convection. The length of the front horizontal faces is 60 mm and the lateral faces have a small thickness of 0.5 mm with the depth of 15 mm. The results are simulated for the range of Rayleigh numbers ( Ra ), starting from critical R a c (threshold) to 10 R a c to analyze the flow structure of the convective system. At the onset, Ra = R a c , the mean temperature profile is linear and nonlinear for Ra > R a c . The Nusselt number (Nu) values obtained using direct numerical simulations coincide with the analytical results until 5 R a c . For further higher values of Ra > 5 R a c the deviation between the theoretical and computational results are observed. In the range of 2 R a c ≤ Ra ≤ 5 R a c , the wavelength of a cell varies from 2.6 to 3 and accordingly the wavenumber decreases from 2.41 to 1.57. With the augmenting Ra the isotherms show the mushroom-like spreading of cold-descending and warm-ascending currents. The synergy (coordination) between velocity vector and temperature gradient at 5 R a c showed the presence of two sets of anchor shaped profiles of the synergy coefficient. Each set is occupied by the positive and negative synergy coefficients (angle between the velocity and the temperature gradient). These anchor shaped profiles become thinner as Ra increases. The positive and negative regions of the synergy coefficient profiles get interchanged between 9 R a c and 10 R a c .

GNSS VELOCITY AND STRAIN FIELD IN THE NORTHERN SUMATRA 15 YEARS AFTER THE 2004 M9.2 SUMATRA ANDAMAN EARTHQUAKE

The 2004 M9.2 Sumatra-Andaman earthquake in the tectonically active northern Sumatra, could generate postseismic deformation up to a recent period and needs to be considered for earthquake potential study. The GNSS velocities before and 15 years after the earthquake were used to obtain preliminary indicator of whether the postseismic deformation still takes place. Recent velocities were calculated from the horizontal coordinate time series that is obtained using Bernese GNSS software version 5.2. To do this, a comparison was made of velocities and strain rates over two periods. The velocities of 5.5 to 40.5 mm/yr and the strain rate up to 47.2 μstrain/yr were obtained from the recently acquired GNSS data. The pattern for the two-period values can be defined where the direction of vector velocities is trenchward, and extensional behavior occurs more often in the northern area. This indicates that postseismic deformation still occurs therein even 15 years after the earthquake.

The Effect of Flow Sampling on the Robustness of the Actuator Line Method

ABSTRACTThe actuator line method (ALM) is a widely used tool for the modelling of horizontal axis turbines and wind and tidal farm flows. The method uses a virtual blade representation to simulate the dynamics of wind turbines without the computational expense associated with resolving the blade geometry. Within the ALM, the flow is first sampled at each blade section, allowing for the calculation of the sectional lift and drag forces that are in turn imposed on the flow domain using a smearing kernel. In this work, the effect of the flow sampling method on the robustness of the ALM is discussed. Implementations of two widely used types of methods for horizontal axis wind turbines are tested: point sampling, where the flow is sampled at or near the collocation point, and volume average sampling where flow field information from multiple points centred at the collocation point is averaged into a representative blade‐local velocity vector. A third method, line average sampling, that was initially proposed for sampling flows from blade‐resolved simulations is adapted for the ALM framework. This method samples the flow symmetrically around a control element in order to eliminate the interference of the bound circulation, thus allowing the inflow velocity at the aerofoil to be determined. When evaluating power and thrust coefficients and the flow field at the rotor plane predicted by the ALM, the line average sampling approach is demonstrated to be more robust and converges faster with time step for two different rotors: a small wind rotor and a high‐solidity tidal rotor. This suggests that carefully selecting the sampling method could be key in alleviating the very strict time‐step restriction imposed by the ALM, a widely acknowledged limitation of the method. Such an advancement could contribute towards improving the computational efficiency and tractability of the method.

Data-Driven Kinematic Model for the End-Effector Pose Control of a Manipulator Robot

This paper presents a data-driven kinematic model for the end-effector pose control applied to a variety of manipulator robots, focusing on the entire end-effector’s pose (position and orientation). The measured signals of the full pose and their computed derivatives, along with a linear combination of an estimated Jacobian matrix and a vector of joint velocities, generate a model estimation error. The Jacobian matrix is estimated using the Pseudo Jacobian Matrix (PJM) algorithm, which requires tuning only the step and weight parameters that scale the convergence of the model estimation error. The proposed control law is derived in two stages: the first one is part of an objective function minimization, and the second one is a constraint in a quasi-Lagrangian function. The control design parameters guarantee the control error convergence in a closed-loop configuration with adaptive behavior in terms of the dynamics of the estimated Jacobian matrix. The novelty of the approach lies in its ability to achieve superior tracking performance across different manipulator robots, validated through simulations. Quantitative results show that, compared to a classical inverse-kinematics approach, the proposed method achieves rapid convergence of performance indices (e.g., Root Mean Square Error (RMSE) reduced to near-zero in two cycles vs. a steady-state RMSE of 20 in the classical approach). Additionally, the proposed method minimizes joint drift, maintaining an RMSE of approximately 0.3 compared to 1.5 under the classical scheme. The control was validated by means of simulations featuring an UR5e manipulator with six Degrees of Freedom (DOF), a KUKA Youbot with eight DOF, and a KUKA Youbot Dual with thirteen DOF. The stability analysis of the closed-loop controller is demonstrated by means of the Lyapunov stability conditions.

DESIGN OF AN AUTOMATIC PENDULUM VELOCITY MEASURING DEVICE USING LIGHT SENSORS

The instantaneous velocity of an object is the rate of change of its position over an infinitesimally small-time interval, making direct measurement with tools like stopwatches impractical. Using two LDR sensors paired with an Arduino, it is possible to measure such small-time intervals effectively. Understanding the maximum velocity of a mathematical pendulum is critical for distinguishing between harmonic and non-harmonic oscillations. To validate the accuracy of the sensor-Arduino system, several experiments were conducted, including comparisons between Arduino measurements and those obtained from a movie tracker, as well as variations in sensor separation distances, initial oscillation angles, and pendulum rope lengths. Results showed a high level of agreement between Arduino and movie tracker measurements for pendulum crossing times. Additionally, the sensor-Arduino system successfully differentiated the effects of varying each parameter while holding others constant. The system demonstrated an accuracy of 97.86% for velocity measurements at a release angle of 5°, with an average recorded velocity of 23.350 m/s. These findings confirm the sensor-Arduino system's capability to reliably measure the velocity of a mathematical pendulum.

GraphVelo allows inference of multi-modal single cell velocities and molecular mechanisms.

RNA velocities and generalizations emerge as powerful approaches for exacting dynamical information from high-throughput snapshot single-cell data. Several inherent limitations restrict applying the approaches to genes not suitable for RNA velocity inference due to complex transcriptional dynamics, low expression, or lacking splicing dynamics, and data of non-transcriptomic modality. Here, we present GraphVelo, a graph-based machine learning procedure that uses RNA velocities inferred from existing methods as input and infer velocity vectors lie in the tangent space of the low-dimensional manifold formed by the single cell data. GraphVelo preserves vector magnitude and direction information during transformations across different data representations. Tests on multiple synthetic and experimental scRNA-seq data, as well as multi-omics datasets demonstrate that GraphVelo, together with downstream Dynamo analyses, extends RNA velocities to multi-modal data and reveals quantitative nonlinear regulation relations between genes, different layers of gene regulation, and between virus and host cells.

Transition from random self-propulsion to rotational motion in a non-Markovian microswimmer

Abstract We study the motion of an inertial microswimmer in a non-Newtonian environment with a finite memory and present the theoretical realization of an unexpected transition from its random self-propulsion to rotational (circular or elliptical) motion. Further, the rotational motion of the swimmer is followed by spontaneous local direction reversals yet with a steady state angular diffusion. Moreover, the advent of this behaviour is observed in the oscillatory regime of the inertia-memory parameter space of the dynamics. We quantify this unconventional rotational motion of microswimmer by measuring the time evolution of direction of its instantaneous velocity or orientation. By solving the generalized Langevin model of non-Markovian dynamics of an inertial active Ornstein-Uhlenbeck particle, we show that the emergence of the rotational (circular or elliptical) trajectory is due to the presence of both inertial motion and memory in the environment.