Increase In Oscillation Frequency Research Articles

Direct Numerical Simulation of Water Droplets in Turbulent Flow

Details on the fall speeds of raindrops are essential in both applications and natural events, such as rain-rate retrieval and soil erosion. Here, we examine the influence of turbulence on the terminal velocity of two water drops of different sizes. For the first time, computations of droplets in turbulent surroundings are conducted with a direct numerical simulation code based on a volume of fluid method. Both the drop surface deformation and internal circulation are captured. The turbulence intensity at the inflow area, as well as the turbulence length scale are varied. In turbulent flow, we find a decline in the terminal velocities for both drops. Based on the study of the wake flow characteristics and drop surface deformation, the decrease in the terminal velocity is found to be directly linked to a shortening of the wake recirculation region resulting from an earlier and more drastic increase in the turbulence kinetic energy in the shear layer. The turbulent surroundings trigger substantial rises in the drop axis ratio amplitude and a slight increase in the drop oscillation frequency, but barely influence the time-averaged drop axis length.

Nano-oscillators based on a C60 fullerene inside open carbon nanocones: a molecular dynamics study

This study deals with the mechanical oscillatory behavior of a C60 fullerene tunneling through open carbon nanocones (CNCs) using molecular dynamics simulations. The van der Waals (vdW) interactions between two molecules are modeled by Lennard–Jones (LJ) potential, while the interatomic interactions between carbon atoms are modeled by Tersoff–Brenner (TB) potential. Considering the two nanostructures to be either rigid or flexible, a comparative study is conducted to get an insight into the effects of initial conditions (initial separation distance and initial velocity) and geometrical parameters (length and radii of nanocone) on the oscillatory behavior of C60-open CNC oscillators. It is found out that the fullerene molecule performs a uniform oscillation inside open CNCs in the case of rigid nanostructures, whereas it performs a decaying oscillation inside nanocones with a considerable decrease in amplitude and significant increase in oscillation frequency in the case of flexible nanostructures. It is further shown that the preferred position of system corresponding to rigid nanostructures occurs inside of nanocone and close to its small end. On the contrary, this position related to flexible ones changes during the oscillation and moves toward the wide end of nanocone. This study can be used as a benchmark for the improvement of gigahertz (GHz) oscillators and related potential applications together with future developments in the field by extending to fractal calculus.

Research on the influence of ground effect on the performance of robotic fish propelled by oscillating paired pectoral fins

Purpose This paper aims to carry out the research on the influence of ground effect on the performance of robotic fish propelled by oscillating paired pectoral fins. Design/methodology/approach The two-dimensional ground effect model of the oscillating pectoral fin without considering flexible deformation is established by introducing a two-dimensional fluid ground effect model. The parameters of the influence of ground effect on the oscillating pectoral fin are analyzed. Finally, the ground effect test platform is built, and a series of hydrodynamic experiments are carried out to study the influence of ground effect on the propulsion performance of the robotic fish propelled by oscillating paired pectoral fins under different motion parameters. Findings The thickness of the trailing edge and effective clearance are two important parameters that can change the influence of ground effect on the rigid pectoral fin. The experimental results are consistent with that obtained through theoretical analysis within a certain extent, which indicates that the developed two-dimensional ground effect model in this paper can be used to analyze the influence of ground effect on the propulsion performance of the oscillating pectoral fin. The experiment results show that the average thrust increases with the decreasing distance between the robot fish and the bottom. Meanwhile, with the increase of oscillation frequency and amplitude, the average thrust increases gradually. Originality/value The developed two-dimensional ground effect model provides the theoretical basis for the further research on the influence of ground effect on the propulsion performance of the oscillating pectoral fin. It can also be used in the design of the bionic pectoral fins.

Effect of transverse arc oscillation on morphology, dilution and microstructural aspects of weld beads produced with short-circuiting transfer in GMAW

This work investigates the effects of transverse arc oscillation in gas metal arc welding (GMAW) with metal transfer by short circuit using the AISI 316L alloy as the base metal. For this purpose, the influence of the oscillation frequency (f) and the wire-feed speed (Va) at three levels was analyzed, keeping a constant triangular weaving pattern and a fixed welding speed. The results show that an increase in oscillation frequency leads to an increase in the resulting welding speed, resulting in lower welding energy. Regarding weld bead morphology, the transverse arc oscillation reduced the reinforcement, the wetting angle, the penetration and the convexity index (CI < 30%). On the other hand, higher dilution values were obtained. Finally, a clear microstructure refinement tendency became evident when applying the weaving technique.

Impact of the ground effect on the energy extraction properties of a flapping wing

The energy harvesting device with flapping foil has the characteristic of environmental adaptability, particularly in shallow water. This study applies a transient numerical calculation method based on a dynamic grid technique in an absolute coordinate system to analyze the flow fields and pressure distributions of a flapping airfoil near a ground wall. The effects of Reynolds number (Re), average ground clearance, and effective angle of attack on the power extraction efficiency of the flapping airfoil are investigated with respect to variations in the oscillation frequency. The simulation results indicate that the ground effect can greatly increase the power extraction efficiency of the flapping airfoil, and that the highest efficiency is obtained at an optimum average ground clearance. This ground effect is asymmetric over the course of flapping airfoil motion toward and away from the ground wall, and the efficiency is most increased as the airfoil moves far from or closely to the ground wall. The formation of the corresponding divergent or convergent tunnel effects alters the flow fields and pressure distributions around the airfoil near the leading edge, and, in particular, decreases the pressure on the suction side, which results in an overall increase in the heaving force and a correspondingly increased power harvesting capability. With or without the ground effect, the efficiency of the flapping airfoil firstly increases and then decreases with increasing oscillation frequency or effective angle of attack at constant Re and average ground clearance values. Moreover, the positive impact of the ground wall effect on the power extraction efficiency of the airfoil becomes increasingly obvious when the oscillation frequency and the angle of attack are increased simultaneously. Finally, the oscillation frequency obtaining the highest power extraction efficiency in conjunction with the ground effect decreases as the flow fields transition from laminar to turbulent flow with increasing Re.

Steady Flows of a Fluid Oscillating in an Axisymmetric Channel of Variable Cross-Section, Versus the Dimensionless Frequency

The averaged flows excited by oscillations of fluid in an axisymmetric channel, which transverse section periodically changes with longitudinal coordinate, are experimentally studied. Oscillations are caused by harmonious change of a volume of the fluid, which is pumped over via the channel. Researches are executed within the broad range of dimensionless frequency which characterizes the ratio of the cross size of the channel to the thickness of Stokes boundary layers. It is shown that oscillations of fluid excite an averaged flows in the form of a system of toroidal vortex structures in each segment of the channel. The intensity of averaged flows increases with the increase in amplitude and frequency of fluid oscillation and is defined by the pulsational Reynolds number and the dimensionless frequency in the channel of the set geometry. It is shown that in the limit of low dimensionless frequencies, when viscous forces define the oscillating component of flow in the whole channel, the primary vortices occupy all the volume of the channel. The cross size of the primary vortices decreases with the increase in dimensionless frequency, and at high frequencies the vortexes are localized in viscous boundary layer near the side border in a narrow part of the channel. At the same time, the secondary vortices having opposite turning are formed outside the primary boundary layer vortexes in the bulk of the channel. The transformation of the structure of averaged flows and their intensity versus the dimensionless frequency are studied.

Reduced-order modeling of dynamic stall using neuro-fuzzy inference system and orthogonal functions

To consider stall flutter in the design procedure of a blade, accurate models of flow loading are needed. This paper first presents a numerical simulation of an airfoil undergoing a deep dynamic stall employing a computational fluid dynamics code. Overset and polyhedral grid techniques are adopted to accurately simulate the flow field at high angles of attack. Having validated the simulation, the occurrence of stall flutter over a pitching airfoil with an increase in amplitude and frequency of oscillations is examined. The results express that the amplitude of the lift and pitching moment depends on the amplitude of the forced oscillation and there are higher harmonics of the pitching moment compared to the forced oscillation frequency content, both indicating the nonlinearity of aerodynamic lift and pitching moment. Subsequently, a nonlinear reduced model of the dynamic stall is derived using a fuzzy inference system (FIS) and the adaptive network-based FIS (ANFIS). Due to the unsatisfactory results of modeling, especially at post-stall angles of attack, the Gram–Schmidt orthogonalization technique is used to construct a more complex structure of the input variables. The new higher-order input variables have been re-employed by FIS and ANFIS. The results show that excellent modeling is achieved by ANFIS between the new structure of the inputs and the corresponding aerodynamic coefficients using only 10% of input–output data. Having found an appropriate relation, the proposed reduced-order model could properly predict the aerodynamic response of the pitching airfoil at two reduced frequencies.

Experimental study on the oscillation characteristics of thin liquid film in a microchannel

Characterization of thin liquid film is important for comprehensive understanding the phase-change heat transfer mechanisms in an oscillating slug flow. In this study, the thin film thickness of oscillating slug flow in a square tube was experimentally investigated using a nano-particle tracking velocimetry technique. Square tubes with inner dimension of 3.0 × 3.0, 1.6 × 1.6, 0.5 × 0.5, and 0.3 × 0.3 mm2 were used for test tubes, water was used as test fluids. The results show asymmetric velocity distribution in the thin liquid film. An obvious decrease of response time was observed for the thin liquid film when the oscillation frequency increases. The measured thin film thickness fits well with Taylor’s law when the capillary number is small. Deviation from Taylor’s law was found for larger capillary number, due to the prominent effect of bubble deceleration on the thin film thickness when the oscillation frequency increases. The relationship between acceleration process and deceleration process in different oscillation frequency is also studied.

Few-nm tracking of current-driven magnetic vortex orbits using ultrafast Lorentz microscopy

Transmission electron microscopy is one of the most powerful techniques to characterize nanoscale magnetic structures. In light of the importance of fast control schemes of magnetic states, time-resolved microscopy techniques are highly sought after in fundamental and applied research. Here, we implement time-resolved Lorentz imaging in combination with synchronous radio-frequency excitation using an ultrafast transmission electron microscope. As a model system, we examine the current-driven gyration of a vortex core in a 2 μm-sized magnetic nanoisland. We record the trajectory of the vortex core for continuous-wave excitation, achieving a localization precision of ±2 nm with few-minute integration times. Furthermore, by tracking the core position after rapidly switching off the current, we find a transient increase of the free oscillation frequency and the orbital decay rate, both attributed to local disorder in the vortex potential.

Evaluation of a Dynamic Transfer Matrix for a Hydraulic Turbine

Abstract It is well known that hydraulic machines experience various types of flow instabilities causing a negative influence on the system under off-design operations. The transfer matrix method correlating the flow properties in upstream and downstream of hydraulic machines is widely adopted as a first step to investigate dynamical characteristics of flow. Transfer matrix elements are the key to understand hydraulic system stability. This study focuses on measurements of transfer matrix elements for a hydraulic turbine. The oscillations of the flowrate are produced by two flow exciters located in upstream and downstream of the turbine, and evaluated from the fluctuations of the pressure difference across two streamwise locations. It is shown that the transfer matrices are successfully evaluated at part load and full load operations in the presence and absence of cavitation. In particular, cavitation compliance and mass flow gain factor, which determine the dynamical response of cavitation to the change of pressure and flowrate, are calculated from the measured transfer matrix elements. The absolute value of both cavitation compliance and mass flow gain factor is found to increase with respect to the decrease of the cavitation number. The phase of the mass flow gain factor is delayed as the excitation frequency increases. This suggests that hydraulic systems may be stabilized when the oscillation frequency increases. As a result of stability analyses, it is demonstrated that the mass flow gain factor plays a crucial role, especially in the full load cavitation surge.

Laboratory Flume Experiments on Cohesive Sediment Erosion by Oscillating Wall Jet

Dong, C.; Zhao, P.; Yu, G., and Zhang, M., 2021. Laboratory flume experiments on cohesive sediment erosion by oscillating wall jet. Journal of Coastal Research, 37(1), 179–190. Coconut Creek (Florida), ISSN 0749-0208.Jet scour, a common method of dredging clay, must be accurately estimated. Cohesive sediment is aggregated by adhesion and is sensitive to erosion when the flow shear is appended with oscillation, as indicated by sediment rheology. On the basis of sediment rheology, this study experimentally investigates the timescale of the erosion of cohesive sediment under an oscillating wall jet in a laboratory flume. The oscillating wall jet is induced by a swinging oblique impingement jet. The erosion of the cohesive sediment was performed under an oscillating wall jet with a fixed flow rate but different oscillating intensities. The morphological properties, scouring depths, and rheological characteristics of the sediment were observed. The results show that when the oscillating frequency is zero or low, the sediment particles scatter similarly to aggregates, forming ridges at the intersection of the scouring slope and bed surface. However, these aggregates and ridges disappear when the oscillating frequency increases. Further, evaluations of the cohesive sediment under different oscillating frequencies indicate that the yield stress decreases with an increase in the scouring frequency. Submerged cohesive sediments tend to fluidize under oscillating shear, which indicates shear thinning behavior. Under the conditions of the oscillating wall jet, the scouring depth of the cohesive sediment increases exponentially with the oscillating intensity.

A comparative analysis of two approaches to damping of vibrations

In the current paper a comparison between two approaches to damping of vibrations is presented. A comparative analysis was carried-out on the example of a cantilever plate. In the first case, the surface of the plate was covered with a layer of viscoelastic material. Its mechanical behavior is described by equations of the linear theory of viscoelasticity based on complex dynamic moduli. In this case, the complex dynamic moduli can increase or decrease as the oscillation frequency increases, or remain constant. It is assumed that the thickness of the viscoelastic layer is equal to the thickness of the plate.In the second case piezoelectric elements shunted with resistive (R) or resonant (RL) electric circuits were applied for damping of vibrations. In this case, for each vibration mode, the optimal location of the piezoelectric element and the parameters of the external electrical circuit are determined. The comparison is carried out on the basis of analysis of the vibration damping coefficients determined by the value of the complex natural vibration frequencies obtained from the solution to the problem of natural vibrations for electro-viscoelastic bodies with external electric circuits. Numerical implementation was performed using finite element method.

The effects of high-frequency chest compression on end-tidal CO2.

High-frequency chest compression (HFCC) is used for airway clearance, but may have other effects. We sought to determine if HFCC provides augmented ventilation. During treatment, capnometry was measured with the HFCC vest set to 6-20 Hz. End-tidal CO2 (etCO2 ) was compared using generalized estimating equations. Twenty-four measurements were obtained from 15 subjects with mean age 15.2 ± 2.5 years and forced expiratory volume in one second (FEV1 ) % predicted 70 ± 23. EtCO2 decreased with HFCC at 6 Hz when compared with baseline (P < .001), with small changes with increasing oscillation frequency. Change in etCO2 was not predicted by FEV1 , body mass index, age, or sex. While HFCC has been shown to be a suitable method of airway clearance, investigators have failed to demonstrate differences between techniques. Assessment of these methodologies will become important as new airway clearance devices are proposed. Other outcome measures (besides FEV1 ) may be needed to assess effects of airway clearance, and we propose that physiologic measures might be one such measure which deserves further exploration.

The rheological properties and emulsifying behavior of polysaccharides sequentially extracted from Amana edulis

The rheological properties and emulsifying behavior of four polysaccharides (HBSS, CHSS, DASS, and CASS) sequentially extracted from Amana edulis (AEPs) were investigated under various concentrations, temperatures, pH levels, and ionic strengths. The apparent viscosity of the four AEPs solutions at 1% (w/w) concentration were found to be CHSS > DASS > HBSS > CASS. When the AEPs were heated to 100 οC, they showed lower colloidal viscosity, whereas after refrigeration and chilling, higher apparent viscosities were observed. The apparent viscosity of four AEPs at pH 10 or pH 4 was lower than that at pH 7. The apparent viscosity increased at a lower sodium ion concentration and then declined with an increase in ion concentration. The storage modulus (G′) and loss modulus (G″) increased with an increase in oscillation frequency. The emulsifying activity and stability were enhanced as the concentration of the four AEPs increased. The emulsifying activity and stability of the AEPs were steady within the pH range of 2–10 and NaCl concentration range of 0–0.4 mol/L. Our results implied that these polysaccharides can be utilized as a novel hydrocolloid source for natural thickeners in the food industry.

An experimental study of the dynamic aerodynamic characteristics of a yaw-oscillating wind turbine airfoil

The design of large wind turbines requires a comprehensive and accurate analysis of the dynamic loads of airfoils, so it is of great importance to study the dynamic aerodynamic characteristics of a yaw-oscillating airfoil. In this paper, using “electronic cam” technology and synchronous acquisition of dynamic data, a wind tunnel test of yaw oscillation for the airfoil dynamic “sweep effect” is carried out for the first time, providing previously missing lateral dynamic test data. The results show that the aerodynamic curves of the yaw-oscillating airfoil have an obvious hysteresis effect, induced mainly by a periodic pressure fluctuation on the airfoil suction surface, and the aerodynamic hysteresis characteristics are enhanced with increasing oscillation frequency, initial angle of attack, and amplitude. The hysteresis loops of the lift and pressure drag, as a function of yaw angle, follows a “W” shape, the hysteresis loop of the pitching moment follows an “M” shape, and the hysteresis loop of the unsteady lift increment follows an “∞” shape. The aerodynamic force of the airfoil under negative stroke is higher than that under positive stroke, and the aerodynamic coefficients decrease clearly with increasing oscillation frequency under positive stroke. The pressure fluctuation on the airfoil surface is due to a periodic generation, development, movement, breakdown, dissipation, and reconstruction of shear layer vortices, leading edge vortices, trailing edge vortices, and dynamic separation vortices. The dynamic aerodynamic hysteresis of the yaw-oscillating airfoil occurs essentially because of the dynamic interaction between vortex and vortex, or vortex and airfoil surface boundary layer.

1975-P: Increased Pancreatic a Cell Ca2+ Oscillations Explain Hyperglucagonemia in High-Fat Diet-Fed Mice

Glucagon secretion from pancreatic α cells is elevated in obesity, exacerbating hyperglycaemia and contributing to the development of diabetes. α cells exhibit intracellular calcium (Ca2+i) oscillations, which drive glucagon secretion. To understand these oscillations and their contribution (if any) to the diabetic phenotype, we developed a mouse model for studying α cell Ca2+i, and used this to investigate α cell Ca2+i dynamics in mice exposed to a high fat diet (HFD). Mice expressing GCaMP3 specifically in α-cells (GcgCre x GCaMP3 reporter mouse) were fed a control (10% fat; CTL) or high fat diet (60%; HFD) for 12 weeks. Mice then underwent a glucose tolerance test (GTT). Ca2+i imaging and glucagon secretion experiments were carried out on isolated (ex vivo) islets. HFD mice had impaired glucose tolerance compared to CTL mice (p&amp;lt;0.0001, n=25 mice). Plasma glucagon was suppressed by high glucose in CTL (p=0.01), but not HFD mice (p=0.65; n=10-20 mice). In islets from both CTL and HFD mice, Ca2+i oscillation frequency was suppressed by high glucose (p&amp;lt;0.0001 n=200-250 cells, 6 islets, 3 mice). However, oscillation frequency was higher in HFD mice vs. CTL (p&amp;lt;0.0001; n= 203-252 cells, 6-9 islets, 3 mice). Oscillation amplitude was not altered by glucose in CTL or HFD mice (p=0.076 and 0.87 respectively, 31-67 cells, 6-7 islets, 3 mice). Pharmacological approaches suggested that the increase in oscillation frequency was not due to altered α cell fat metabolism (p=0.5 38-68 cells, 4 islets, 3 mice). Insulin secretion from ex vivo islets was elevated in HFD vs. CTL mice, although this did not reach significance (p=0.084; N=6 mice). These preliminary data suggest that hyperglucagonemia in HFD mice may have origins intrinsic to the islet. This was not due to reduced paracrine regulation by insulin, as insulin secretion was elevated in HFD mice. Future experiments will aim to fully power this study and understand whether α cell intrinsic mechanisms contribute to the hyperglucagonemic phenotype. Disclosure J. Kellard: None. L. Briant: None. J.G. Knudsen: None. P. Rorsman: None. Funding UK Wellcome Trust

Japanese grape (Hovenia dulcis) polysaccharides: New insight into extraction, characterization, rheological properties, and bioactivities

In this study, accelerated solvent extraction (ASE) technology was applied to extract Hovenia dulcis polysaccharides (HDPs). The polysaccharide yields, physicochemical properties, rheological properties, antioxidant activities, and hypoglycemic effects were compared between ASE-HDPs and hot water extracted polysaccharides (HWE-HDPs). The maximum ASE-HDPs yield was obtained using a response surface method (RSM) with optimized ASE conditions comprising 2 cycles at 130 °C for 23 min. The maximum ASE-HDPs yield of 8.62 ± 0.29% is significantly higher than the maximum HWE-HDP yield of 6.89 ± 0.21%. The chemical compositions, molecular weight (Mw) distributions, rheological properties, antioxidant activities, and hypoglycemic effects of polysaccharides varied with each extraction method, while the primary structure remained the same. Both HDPs exhibited typical shear thinning behavior and non-Newtonian properties. The storage modulus (G′) and loss modulus (G″) of the HDPs solutions were enhanced with increasing oscillation frequency, and displayed gelatinous behavior (G′ > G″). ASE-HDPs displayed better antioxidant activities in DPPH and ABTS, as well as superior reducing power and hydroxyl and superoxide anion scavenging ability, whereas HWE-HDPs exhibited higher Fe2+ chelating activity. The in vitro experiments indicated that HDPs have a decidedly hypoglycemic effect.

Numerical study on the turbulent mixing in channel with Large Eddy Simulation (LES) using spectral element method

Turbulent mixing is an important thermal hydraulic phenomenon in the reactor core rod bundles and it leads to strong momentum and energy transfer among adjacent subchannels in fuel assembly. Generally, turbulent mixing coefficient is usually referred to describe turbulent effect, which commonly sets to a constant or calculated utilizing Reynolds number dependent fitting correlations based on experimental data.In this paper, a high-scalable and high-performance spectral element method combining with high passed filtered Large Eddy Simulation (LES) model has been proposed to simulate the turbulent flow through parallel wall channel and square channel with a cylindrical rod for single-phase flow. In the parallel wall channel case, mesh sensitivity analysis and model validation were accomplished by comparing the simulation data with DNS references utilizing key parameters such as velocity profile and stresses in the near wall region. Meanwhile, for the square channel with a cylindrical rod case, instantaneous lateral velocity monitored in the gap center has been compared with the experimental data with different Reynolds numbers and geometric conditions. From the simulation approach, both the absolute oscillation amplitude and the oscillation frequency increase with the pitch diameter ratio. Finally, the simulation results of turbulent mixing coefficient dependent on Reynolds number were validated with both experimental and theoretic references to demonstrate the feasibility of spectral element method combining with LES model. The root mean square (RMS) value of lateral fluctuating velocity was adopted to reflect the effective mixing capability, predicting the turbulent mixing phenomena with a reasonable degree of accuracy from the specific calculation strategy. Fast Fourier Transform (FFT) also performed and got an agreement with reference data.

Chemical and rheological properties of proteoglycans from Sarcandra glabra (Thunb.) Nakai.

Two proteoglycans (HPP and LPP) with different ratios of protein/polysaccharide were extracted from S. glabra. The chemical compositions, relative average molecular weights, monosaccharide compositions, FT-IR spectra, and rheological properties of the two proteoglycans were determined. The results exhibited that the two proteoglycans had pseudoplastic fluids properties and displayed shear-thinning behavior. The apparent viscosity of the two proteoglycans both increased with increasing concentrations. The temperature had different effects on the viscosity of the two proteoglycans. As temperature increased from 25 to 85 °C, the viscosity of LPP descended while the HPP's viscosity rose first and then dropped slightly. The effects of CaCl2 addition on the two samples were like that of the temperature. The viscosities of HPP and LPP had different tolerances to acidity and alkalinity. HPP solution was more sensitive to pH changes due to its high protein content. The addition of sucrose increased the viscosities of samples. The modulus G' and G″ of HPP and LPP were increased with the increase of oscillation frequency, while the crossover points of G' and G″ values decreased with the increasing concentrations of HPP and LPP. The above data presented that the two proteoglycans could be promising candidates for food industries and pharmacological applications.

Effect of Piezo-Embedded Inverted Flag in Free Shear Layer Wake

The use of flexible inverted piezo embedded Polyvinylidene Difluoride (PVDF) as a simultaneous energy harvester and as a wake sensor is explored. The oscillation amplitude (characterized by voltage output) and oscillation frequency of the piezo-embedded PDVF was quantified in the wake of a 2D NACA 0012 model and SD7003 model at a Reynolds number of 100,000 and 67,000, respectively. The performance of the sensor was also quantified in the freestream without the presence of the wing. In order to quantify the sensor response to angle of attack and downstream distance, the amplitude and frequency of oscillations were recorded in the wing wake. Increase in angle of attack of the wing resulted in increase in oscillation frequency and amplitude of the PVDF. The results also indicated that the inverted flag configuration performed better in the wake under unsteady conditions when compared to freestream conditions. The results from Particle Image Velocimetry indicated that the wake signature was not affected by the presence of the PVDF in the wake. The root mean square voltage contours in the wake of SD7003 airfoil show remarkable free shear layer wake features such as upper and lower surface stratification and downwash angle which shows the sensitivity of the sensor to the unsteadiness in the wake. The capability of this device to act as a potential energy harvester and as a sensor has serious implications in extending the mission capabilities of small UAVs.