Laminar Vortex Research Articles

Measurements of Natural Turbulence During the BOLT II Flight Experiment

A Mach 6.0 flight experiment was performed to characterize the turbulent skin friction and heat flux associated with natural transition for vehicle-length Reynolds numbers up to 45 million. This boundary-layer turbulence flight, termed BOLT II, was the second in a series coordinated by the Air Force Office of Scientific Research. Surface heat flux, skin friction, and pressure fluctuation spectra were acquired to characterize the transition process. The test geometry used concave curvature and swept leading edges to introduce a boundary layer with stationary laminar vortex streaks, competing transition mechanisms, and complex early turbulence. The analyses also showed that the spatial evolution of turbulence varied with respect to the location of the vortex heating streaks. Prominent overshoots were observed in the early turbulence within the streak. Turbulence data was collected for Reynolds numbers ReL up to 45×106. A common Rex=12×106 was identified as the start of equilibrium turbulence for the data presented. Conjugate heat transfer simulations, both laminar and turbulent, agreed well with the experimental data, including the laminar leading edge. The Reynolds analogy ratios based on the curve fits to the data, including compressibility, were generally between 0.9 and 1.0. The observed variations were likely the result of the spatial separation of the sensors and different definitions of Stanton number normalization between flight and theory.

Compressed neural networks for reduced order modeling

Reduced order modeling (ROM) techniques, such as proper orthogonal decomposition (POD) and dynamic mode decomposition (DMD), have been widely used to analyze stationary flows. Neural networks such as autoencoders are effective to reduce the dimension of non-stationary flow, but their larger storage requirements compared to POD and DMD compromise the expectations on ROM. The present work aims at compressing the autoencoder model via two distinctively different approaches, i.e., pruning and singular value decomposition (SVD). The developed algorithm is then applied to reconstruct the flow fields of typical stationary (i.e., a laminar cylinder flow and two turbulent channel flows) and non-stationary (i.e., a laminar co-rotating vortex pair) examples. It is shown that pruning and SVD reduce the size of the autoencoder network to 6% and 3% for the two simple laminar cases (or 18% and 13%, 20%, and 10% for the two complex turbulent channel flow cases), respectively, with approximately the same order of accuracy. Therefore, the proposed autoencoders optimized by the network pruning and SVD lead to effective ROM of both stationary and non-stationary flows although they require more iterations to converge than conventional methods.

Arbitrary-order sensitivities of the incompressible base flow and its eigenproblem

First-order sensitivities and adjoint analysis are used widely to control the linear stability of unstable flows. Second-order sensitivities have recently helped to increase accuracy. In this paper, a method is presented to calculate arbitrary high-order sensitivities based on Taylor expansions of the incompressible base flow and its eigenproblem around a scalar parameter. For the incompressible Navier–Stokes equations, general expressions for the sensitivities are derived, into which parameter-specific information can be inserted. The computational costs are low since, for all orders, a linear equation system has to be solved, of which the left-hand-side matrix stays constant and thus its preconditioning can be exploited. Two flow scenarios are examined. First, the cylinder flow equations are expanded around the inverse of the Reynolds number, enabling the prediction of the two-dimensional cylinder base flow and its leading eigenvalue as a function of the Reynolds number. This approach computes accurately the base flow and eigenvalue even in the unstable regime, providing, when executed subsequently, a mean to calculate unstable base flows. This case gives a clear introduction into the method and allows us to discuss its constraints regarding convergence behaviour. Second, a small control cylinder is introduced into the domain of the cylinder flow for stabilization. Higher-order sensitivity maps are calculated by modelling the small cylinder with a steady forcing. These maps help to identify stabilizing areas of the flow field for Reynolds numbers within the laminar vortex shedding regime, with the required number of orders increasing as the Reynolds number rises. The results obtained through the proposed method align well with numerically calculated eigenvalues that incorporate the cylinder directly into the grid.

IMPACT OF SOLID BOUNDARIES AND VISCOSITY OF THE MEDIUM ON THE CONTRIBUTION OF THE INERTIAL AND VORTEX COMPONENTS OF THE NORMAL FORCE OF A ROTATING PLATE. PART 2

Within the framework of the improved method of discrete vortices, generalized for viscous media, a method has been developed for determining the contribution of forces of inertial, vortex and circulation nature to the normal force of a plate moving in a stationary viscous boundless medium accord- ing to an arbitrary law, in the presence of a wall and in a channel. The developed method was tested for the case of instantaneous angular start of the plate and subsequent constant angular speed of rotation (Wagner's problem) in a viscous boundless medium, in the presence of a wall and in a channel, in laminar and turbulent modes. The application of approximate analytical formulas for the components of the induced velocity from a discrete vortex in a viscous medium near the wall and in the channel made it possible to obtain velocity fields that visualize two vortices separated from the edges of the plate and the dynamics of their dispersion in laminar and turbulent regimes of rotation of the plate near the wall and in the channel. The inertial- vortical nature of the normal force of the plate (with the dominance of inertial forces) is confirmed, which rotates after an instantaneous start with the separation of the flow from both its edges, regardless of the presence of solid boundaries and laminar or turbulent flow regimes. It was found that in the case of the laminar regime, the effect of the presence of the wall on the reduced inertial component of the normal force of the plate is insignificant, but the influence of the channel leads to a faster departure of the laminar vortex from the moving edge of the plate, which leads to a gradual increase in the contribution of the inertial component of the normal force of the plate up to 100 % and more when turning the plate perpendicular to the channel walls. Approximately the same happens in the case of the absence of solid boundaries, when a turbulent vortex of a larger size and intensity than the corresponding laminar one moves away from the moving edge of the plate.

Numerical study of a laminar vortex ring of a polymer solution

Numerical study of a laminar vortex ring of a polymer solution

Cross-Component Energy Transfer in Superfluid Helium-4

The reciprocal energy and enstrophy transfers between normal fluid and superfluid components dictate the overall dynamics of superfluid 4He including the generation, evolution and coupling of coherent structures, the distribution of energy among lengthscales, and the decay of turbulence. To better understand the essential ingredients of this interaction, we employ a numerical two-way model which self-consistently accounts for the back-reaction of the superfluid vortex lines onto the normal fluid. Here we focus on a prototypical laminar (non-turbulent) vortex configuration which is simple enough to clearly relate the geometry of the vortex line to energy injection and dissipation to/from the normal fluid: a Kelvin wave excitation on two vortex anti-vortex pairs evolving in (a) an initially quiescent normal fluid, and (b) an imposed counterflow. In (a), the superfluid injects energy and vorticity in the normal fluid. In (b), the superfluid gains energy from the normal fluid via the Donnelly–Glaberson instability.

NUMERICAL THREE-DIMENSIONAL MODEL OF ULTRASONIC COAGULATION OF AEROSOL PARTICLES IN VORTEX ACOUSTIC STREAMING

Separation of highly dispersed systems with huge liquid-gas or liquid-solid interfaces is relevant for practical tasks of gas purification from the most highly dispersed and difficult-to-detect dispersed fraction PM2.5, and separation of nanoparticles (including their small agglomerates) in fine chemical technology processes. One of the most effective ways to separate highly dispersed systems with a large interface surface is to combine each of the closed subsurfaces (surfaces of individual dispersed particles) under the influence of hydrodynamic effects in the gas phase, arising both near the interface surfaces and at a considerable distance from them, due to the superposition of ultrasonic vibrations. Since the efficiency of ultrasonic coagulation decreases with a large distance between closed subsurfaces from each other in PM2.5 aerosol and the small size of these surfaces, it is necessary to create conditions for the emergence of new nonlinear effects that contribute to the local compaction of the dispersed fraction. In a resonant and significantly inhomogeneous ultrasonic field (with a scale of inhomogeneity on the order of the wavelength), vortex acoustic flows arise, which, due to inertial forces, locally compact the dispersed phase in the form of an increase in the concentration of aerosol particles. A numerical model of ultrasonic coagulation of PM2.5 aerosol particles in three-dimensional (3D) vortex acoustic streaming is proposed in this paper. The model is designed to identify the possibility of increasing the efficiency of ultrasonic coagulation in 3D streaming by virtue of the following mechanisms: (1) local increase in concentration caused by the inertial transfer of particles to the periphery of 3D vortices in the gas phase; (2) increase in the frequency of particle collisions due to 3D turbulent disturbances in ultrasonic fields; and (3) increase in productivity and ensuring uninterrupted implementation of the process in a flow mode owing to transfer of particles between the streamlines of the main vortices initiated by ultrasonic vibrations. The listed mechanisms for increasing the efficiency of coagulation in 3D streaming are taken into consideration by introducing two stream functions, considering turbulent chaotic disturbances of the flow resulting in dispersion of particle velocities. It was possible to establish based on numerical analysis of the model using the example of PM2.5 that laminar vortex flows begin to influence at sound pressure level from 160-165 dB, and turbulent disturbances make an additional contribution in the range of sound pressure levels from 140-170 dB. At the same time, as a result of 3D turbulent disturbances, the efficiency of coagulation reaches almost 100% at a sound pressure level 5 dB lower than with laminar flows (sound pressure amplitude, 3 times lower).

Significant influence of fluid viscoelasticity on flow dynamics past an oscillating cylinder

This study focuses on numerically investigating the impact of fluid viscoelasticity on the flow dynamics around a transversely forced oscillating cylinder operating in the laminar vortex shedding regime at a fixed Reynolds number of $Re = 100$ . Specifically, we explore how fluid viscoelasticity affects the boundary between the lock-in and no lock-in regions and the corresponding wake characteristics compared with a simple Newtonian fluid. Our findings reveal that fluid viscoelasticity enables the synchronization of the vortex street with the cylinder motion at lower oscillation frequencies than those required for a Newtonian fluid. Consequently, the lock-in region boundary for a viscoelastic fluid differs from that of a Newtonian fluid and expands in the non-dimensional cylinder oscillation amplitude and frequency parameter space. In the primary synchronization region, the wake of a Newtonian fluid exhibits ‘2S’ (two single vortices) and ‘P+S’ (a pair of vortices and a single vortex) shedding modes. In contrast, a ‘2P’ (two pairs of vortices) vortex mode is observed for a viscoelastic fluid within the same region. To gain a deeper understanding of the differences in the coherent flow structures and their associated frequencies between the two fluids, we employ the data-driven reduced-order modelling technique, known as the dynamic mode decomposition (DMD) technique. Utilizing this technique, we successfully extract and visualize the two competing fundamental frequencies (cylinder oscillation and natural vortex shedding frequencies) and their associated flow structures in the case of the no lock-in state, whereas only the dominant cylinder oscillation frequency and associated flow structure in the case of the lock-in state. Furthermore, we propose that the presence of excess strain resulting from the stretching of polymer molecules in viscoelastic fluids leads to a distinct difference in the wake structure compared with Newtonian fluids. This observation aligns with the findings obtained from the $Q$ -criterion and vorticity transport analysis of the wake.

Understanding intracranial aneurysm sounds via high-fidelity fluid-structure-interaction modelling

BackgroundSince the 1960s, the origins of intracranial aneurysm bruits and musical murmurs have been debated, with proposed mechanisms ranging from self-excitation (i.e., resonance) by stable pulsatile flow, to vibration caused by unstable (laminar vortex shedding or turbulent) flow. This knowledge gap has impeded the use of intracranial sounds a marker of aneurysm remodelling or rupture risk. New computational techniques now allow us to model these phenomena.MethodsWe performed high-fidelity fluid-structure interaction simulations capable of understanding the magnitude and mechanisms of such flow-induced vibrations, under pulsatile flow conditions. Six cases from a previous cohort were used.ResultsIn five cases, underlying flow instabilities present as broad-band, random vibrations, consistent with previously-described bruits, while the sac also exhibits resonance, rocking back and forth in different planes of motion, consistent with previously described musical murmurs. Both types of vibration have amplitudes in the range of 0.1 to 1 μm. The murmurs extend into diastole, after the underlying flow instability has dissipated, and do not exhibit the characteristic repeating frequency harmonics of previously hypothesized vortex-shedding mechanisms. The remaining case with stable pulsatile flow does not vibrate. Spectrograms of the simulated vibrations are consistent with previously reported microphone and Doppler ultrasound recordings.ConclusionsOur results provide a plausible explanation for distinct intracranial aneurysm sounds and characterize the mechanical environment of a vibrating aneurysm wall. Future work should aim to quantify the deleterious effects of these overlooked stimuli on the vascular wall, to determine which changes to the wall makeup are associated with vibration.

Generation of laminar vortex rings by an impulsive body force

Generation of laminar vortex rings by an impulsive body force

IMPACT OF SOLID BOUNDARIES AND VISCOSITY OF THE MEDIUM ON THE CONTRIBUTION OF THE INERTIAL AND VORTEX COMPONENTS OF THE NORMAL FORCE OF A ROTATING PLATE. PART 1

Within the framework of the improved method of discrete vortices, generalized for viscous media, a method was developed for determining the contribution of forces of inertial, vortex and circulation nature to the normal force of a plate moving in a stationary viscous boundless medium according to an arbitrary law, in the presence of a wall and in a channel. The developed method was tested for the case of instantaneous angular start of the plate and subsequent constant angular speed of rotation (Wagner's problem) in a viscous boundless medium, in the presence of a wall and in a channel, in laminar and turbulent modes. The inertial-vortical nature of the normal force of the plate (with the dominance of inertial forces) was confirmed, which rotates after an instantaneous start with the separation of the flow from both its edges, regardless of the presence of solid boundaries and laminar or turbulent flow regimes. It has been clarified, that in the case of the laminar regime, the influence of the presence of the wall on the reduced inertial component of the normal force of the plate is insignificant, but the influence of the channel leads to a faster departure of the laminar vortex from the front edge of the plate, which leads to a gradual increase in the contribution of the inertial component of the normal force of the plate up to 100% and more at the end of rotation plates. Approximately the same happens in the case of the absence of solid boundaries, when a turbulent vortex of a larger size and intensity than the corresponding laminar one moves away from the leading edge of the plate.

Annular self-organization of the two-dimensional vorticity condensate

Self-organization of the vorticity condensate of forced two-dimensional turbulence is examined in analogy with the mixing of a background planetary vorticity gradient in geophysical flows. Starting from the theoretical vorticity profile of the condensate, different scenarios are illustrated by the construction of idealized angular momentum conserving rearrangements of vorticity into a staircase profile similar to the potential vorticity staircase of $\beta$ -plane turbulence. Two sets of numerical experiments are then presented that illustrate a similar self-organization of the background vorticity gradient in fully turbulent flows. In the first set of experiments, the flow is initialized with a laminar vortex dipole corresponding to the theoretical condensate vorticity profile. A fluctuation vorticity field is then induced by a stochastic forcing at smaller scales, which induces an azimuthally symmetric self-organization of the laminar flow into distinct annular bands. In the second set of experiments, the flow is initialized from rest with stochastic forcing generating a turbulent inverse energy cascade, out of which emerges the condensate in a self-consistent evolution as the turbulent energy accumulates at the domain scale. A self-organization of the condensate is again observed, giving a distinct annular structure on top of the theoretically predicted condensate profile. A major difference from the potential vorticity staircase of geophysical flows is the emergence in many cases of significantly non-monotonic radial vorticity profiles.

Analysis of Flow Characteristics around a Square Cylinder with Boundary Constraint

Based on the two-dimensional hydrodynamic model of the finite volume method and structured multigrid, the flow characteristics around a square cylinder with boundary constraint are analysed. The gap ratio G/D (G is the distance from the cylinder to the channel boundary, and D is the side length of the square cylinder) does not change the four flow patterns. Under the laminar vortex street phase, the boundary constraint only reduces the scale of the vortices. The vortex centres are pressed toward the boundaries of the channel, and a low velocity zone is formed near the boundary, but the law of vorticity attenuation along the flow direction is not changed. The flow pattern classification map shows that the boundary constraint increases the Reynolds number required to generate the turbulence flow pattern, and the range of the Reynolds number in the flow pattern of the laminar vortex street has a maximum increase range. The correlation between the time-averaged drag coefficient or the vortex shedding frequency and Reynolds number under different gap ratios indicates that the resistance of the square cylinder and the vortex shedding frequency increase accordingly with the strengthening of the boundary constraint. When G/D < 3.5, the increase is particularly obvious. Meanwhile, the correlation characteristics between the resistance or the vortex shedding frequency of the square cylinder and the Reynolds number are unrelated to the boundary constraint strength.

Time-Accurate Solution of Unsteady Flows in an Implicit Solver Using Block LUSGS Method

Implicit solvers based on the lower-upper symmetric Gauss–Seidel (LUSGS) method are widely used in Computational Fluid Dynamics (CFD) codes to obtain steady-state solutions using large false-transient time steps. However, the method destroys time accuracy and thus cannot be directly used for true transient problems. For such problems, the LUSGS method has to be used with a dual time-stepping algorithm. In this paper, a modified method that preserves time accuracy and is called the block LUSGS (B-LUSGS) solver is employed to compute unsteady flows using larger time steps. This method is compared with the mentioned dual time-stepping technique used for transient problems. Numerical solutions obtained for Stokes' second problem simulation underline the superior temporal accuracy of the block LUSGS method in computing unsteady flows, even at CFL numbers close to 30. Simulations of 2D laminar and 3D turbulent vortex shedding downstream of a circular cylinder further validate the modified method in accurately predicting unsteady separated flows at a CFL number of 100. Comparisons of overall simulation CPU times show that the B-LUSGS method is at least six times computationally cheaper than the dual time-stepping algorithm that uses the traditional LUSGS solver. Abbreviations: BDF, Backward differentiation formula; CFD, Computational fluid dynamics; CFL Courant–Friedrichs–Lewy; CPU, Central processing unit; DTS, Dual time-stepping; LES, Large-eddy simulation; LUSGS, Lower-upper symmetric Gauss–Seidel; NASA, National Aeronautics and Space Administration; PDE, Partial differential equation; RAM, Random access memory; RANS, Reynolds-averaged Navier–Stokes; SA, Spalart–Allmaras; SST, Shear stress transport.

Vortex dynamics and associated turbulence production in the separated transitional flow and the wake at a moderate Reynolds number

The vortex dynamics in the separated transitional flow and the near-wake over a C4 compressor blade at Rec = 24,000 and incidence angles of 0°, 2.5°, 5°, 7.5°, and 10° are investigated experimentally. The laminar separation vortex shedding, the trailing edge vortex shedding, and the interaction of the two vortices are captured using the time-resolved particle image velocimetry. To separate the contributions to the overall turbulence production due to various flow dynamics, the orthonormality of proper orthogonal decomposition modes of the velocity components is utilized. When the laminar separation is close to the trailing edge, the laminar separation vortex locks in the wake instability with an approximately subharmonic of the von Karman frequency. Approximately 80 % of the turbulence is produced by the large-scale flow structure governed by the laminar separation vortex and trailing edge vortex. When the shear layer separates near the leading edge, the laminar separation vortex shedding frequency is lower with a smaller streamwise wavelength. The turbulence production rate contributed by the laminar separation vortex shedding increases with incidences. These novel experimental findings offer insight into transition mechanisms and turbulence modeling of the separated flow located near periodic wake flow.

Exploration and remediation ability test of indigenous bacteria from rice field pemalang regency on lead (Pb) contamined soil

The research aims to obtain isolates and determine the morphological characteristics of bacteria that are resistant to Lead (Pb) contamination. The materials and tools used were soil from conventional rice farming land, Nutrient Agar (NA) medium, alcohol 70%, aquades, PbNO3 solution, aluminum foil, cling wrap, heat-resistant plastic, spiritus, physiological solution of 0.85% NaCl, autoclave, test tubes, petri dishes, erlenmeyer flasks, measuring cylinder, beaker glass, laminar air flow (LAF), shaker, magnetic stirrer, micropipette, refrigerator, analytical balance, ose needle, pH meter, vortex, ice box, shovel , tube racks, bunsen, stationery, labels, and other supporting materials and equipment. This research is a sampling research and continued with laboratory tests including bacterial isolation, colony count calculation and macromorphological characterization. The data obtained from morphological observations are presented in the form of descriptions, while quantitative data are presented in the form of numbers and are used as primary data. The results of isolating bacteria with NA medium added with 5 ppm lead, there are five bacterial isolates were selected, namely KMPb O, KT1Pb C, KT2Pb H, KB1Pb H, and KB2Pb K. Based on the TPC (Total Plate Count) test with a range of 30-300 colonies, the number of bacterial colonies ranged from 10,45 x 106 – 28,9 x 106 CFU/ml. The colony morphological characteristics of the five bacterial isolates were dominated by round in shape, smooth texture and flat elevation.

Buoyancy force and magnetic field effects on laminar vortex breakdown and fluid layers

In this study, the Generalized Integral Transformation Technique (GITT) is used to describe the effect of buoyancy force and magnetic field on the vortex breakdown process generated by the rotation of an electrically conductive fluid. A magnetic field is positioned vertically to stabilize the swirling flow caused by the rotation of the bottom disc of a cylindrical recipient. Three fluids were compared in this study where the range of Richardson number is 0 ≤Ri ≤2.0. When the temperature difference is greater than Ri = 0.1, many layers become visible. These stratified flu id layers act as thermal insulators. In the case of stratification, the increased magnetic field reduces the total number of layers formed in the fluid. The influence of gradient temperature on the distribution of the layers generated is discussed. The limitations between the multilayer structure and the monolayer structure for three fluids are calculated as a function of the flow parameters.

Investigation of natural convection heat transfer of self-heating packed beds

This study investigated heat transfer characteristics of natural convective flow in the packed bed geometry experimentally and numerically. The natural convection experiments for self-heating condition were performed using the copper sulfate electroplating system based on the analogy between heat and mass transfers. Also, the same conditions were simulated with Lattice-Boltzmann Method (LBM) and the results were compared. The spheres diameters were d = 4, 6 and 10 mm and the corresponding Rayleigh numbers were 5.43 × 106, 1.83 × 107 and 8.48 × 107 respectively. The packed bed height to sphere diameter ratios, H/d were 5, 10 and 20. The Nusselt numbers (Nud), velocity and shear stress distributions of both analyses were in good agreement. Both results showed the same order (10−2 m/s) of irregular velocity distributions resulting from the random arrangement of the spheres. In spite of the laminar flow condition, wake and vortex generated by the packed bed geometry increased the turbulent kinetic energies to one- or two-order higher values than those at the entrance. The temperature profiles of flow inside packed bed were approximately uniform for d = 4 mm cases but there were temperature gradients in case of d = 10 mm. This revealed that the use of smaller fuel sphere can prevent from unwanted hot spots inside the packed bed. The Nud values from LBM results and newly developed empirical correlation for natural convective flow in packed bed were consistent.

Electromagnetic tailoring of vortex patterns in an electrolyte layer at the millimeter scale

The action of Lorentz forces in electroconductive fluids is able to enhance the transfer of heat and mass by promoting stirring in a controlled manner. This is particularly important at small scales where Lorentz forces have been used to accelerate electrochemical reactions or modify the morphology of electrodeposits. In this paper, we show that different laminar vortex patterns in a weak electrolyte layer can be tailored on a millimeter scale by electromagnetic stirring generated by the interaction of a dc current and different distributions of neodymium magnets of 1.5 mm diameter. We report particle image velocimetry measurements and neatly visualized images obtained by long exposure photography of steady electromagnetically driven flows that take place in a 10 mm × 10 mm region with a layer thickness of 1 mm. Owing to the weak strength of the Lorentz force and to the millimeter scale confinement of the shallow electrolyte layer, a Reynolds number of Re≈2 was reached. Under these conditions, flow quasi-two-dimensionality is achieved, which is quantitatively verified through a numerical model that is able to replicate the experimental results with a high degree of accuracy. Results show that Lorentz forces can be tailored on a millimeter scale to promote vortex flow patterns that can improve transport processes.

Near Field Evolution of Blade Wakes Under the Influence of Upstream Transitional Flow in a Compressor Cascade at Moderate Reynolds Numbers

Abstract The variation of blade wake characteristics under the influence of upstream transitional flow has not been thoroughly studied, since few control volumes in experimental investigations capture both the blade surface transitional flow and the downstream wake. In this study, instantaneous flow fields in the near-blade and the near-wake region of a compressor cascade at various incidences (i = 0 deg, 2.5 deg, 5 deg, 7.5 deg, and 10 deg) were investigated using particle image velocimetry (PIV). The mean and fluctuating near-wake fields of the compressor blade at Rec = 24,000 were analyzed considering the upstream blade surface laminar separation bubble (LSB) types. The suction-side flow topology shifts at a critical incidence angle of 5 deg from laminar separation without reattachment (i < 5 deg) into a LSB near the trailing edge (i = 5 deg) and an LSB which is advancing to the leading edge (i > 5 deg). The laminar separation vortices retain sufficient strength and coherence to interact with the wake at the low incidence angles (LIA cases, i ≤ 5 deg) but lose coherence beyond the reattachment point at the high incidence angles (HIA cases, i > 5 deg). Self-similarity of the asymmetrical wakes under the influence of various LSB types was established. Near field evolution of wake width, wake decay rate, and flow fluctuations are directly correlated with the LSB type. An optimal incidence exists for the minimum overall flow fluctuation with a delayed separation and alleviated vortical interactions when the LSB locates at the trailing edge.