Doppler Velocimeter Research Articles

Laser doppler device for simultaneous measurement of the velocity and size of aerosols in the nozzle flame

Liquid aerosol is used in technological processes in mechanical engineering, instrument building, chemical industry, medicine and agriculture and other areas. Nozzles are used to spray liquids, which allow to obtain their uniform distribution on the surface or in the volume. In aviation jet engines, fuel is sprayed using nozzles. The thrust of an aircraft engine depends on the quality of fuel atomization. Information on the distribution of droplet sizes and their movement velocity is required to assess the properties of the entire droplet-air system of the nozzle torch. To determine the main characteristics of the nozzle, you need to have a device that measures the velocity of aerosols and the size of aerosols in the nozzle flame. In order to solve this problem, the possibility of using a laser Doppler velocitymeter is investigated. Analysis of the radiation scattered by aerosols by intensity and state of polarization was carried out. It is proposed to increase the signal/interference ratio of the device by ensuring the matching of scattered radiation by intensity and polarization state. For this purpose, it is proposed to install a spatial filter of scattered laser radiation in the device. Such a filter should have the form of a diaphragm with two holes in the form of a narrow slit. Within the limits of one hole, the condition of complete matching of radiation in terms of intensity will be fulfilled, and within the limits of the other hole, the condition of matching according to the state of polarization will be fulfilled. It is shown that if such a receiving diaphragm is inserted into a differential-type laser velocity meter, it can be used to simultaneously measure the velocity and size of aerosols in the nozzle plume. The laser velocity meter photo detector must contain a built-in amplifier with a wide bandwidth. Doppler signals must then be sent simultaneously to an amplitude detector and a digital device. Using a digital device, the frequency of the variable component of the signal will be measured, which is proportional to the velocity of the aerosol and the amplitude of the signal is measured which is proportional to the size of the aerosol.

Analysis of the Capacity of a Double Rating Curve to Reproduce the Flows Measured by Doppler Fixed at the Bottom of an Ice Covered River

The classic approach for estimating river flows is based on the use of a rating curve, which links the flow rates to the water heights measured at a gauging station. This simple approach, has practical and economic advantages but also has limitations related in part to the difficulty of obtaining a representative range of flows, particularly in the presence of ice cover. The objective of this study is to show how it is possible to improve the results obtained by a traditional rating curve using the validated measurements of the Acoustic Doppler Velocity Meter (ADVM) of the Argonaut SW (shallow water) Doppler obtained in continuous, in the presence of ice sheet. The proposed methodology consists in filtering and validating the height measurements provided by the standard gauge as well as the speed and height the measurements provided by the Doppler SW. The validated measurements are then split into two parts: The first part is used for the calibration of a double rating curve that links the series of validated levels obtained by the standard limnimeter, to the flow obtained from the Doppler SW. The second part is used to evaluate the capacity of the double rating curve obtained during the calibration, and to estimate the flow measured by the Doppler SW. The double rating curve thus calibrated reproduces the flow measured by the Doppler SW with an average deviation of 5.03%. In the presence of ice cover, this average difference is 7.68%. These results show the interest of a combined use of the Doppler SW and the double rating curve, for monitoring river flows under ice cover. The Doppler SW makes data available, necessary to calibrate a reliable rating curve, based on a wide range of flow variations covering the winter period.

Experimental and numerical study on the flow characteristics of slug flow in a horizontal elbow

• Phase distribution of gas-liquid two-phase slug flow at the elbow was clarified. • Effects of elbow on flow characteristics at slug flow were analyzed. • A CFD simulation method for slug flow at the elbow was presented. Elbow is one of the most accident-prone locations in multiphase flow lines, and understanding the flow field is the key to manage the risk. In the meantime, the flow characteristics of slug flow are most complicated in the flow field. To clarify the flow characteristics of slug flow at the elbow, the influence and mechanism of the elbow on the flow characteristics of slug flow under different superficial gas-liquid velocities were studied with experiments and numerical simulations. A set of transparent loops with gas-liquid two phase flow was built. High-speed camera, pressure sensor, Doppler velocimeter and wire mesh sensor were used to collect flow pattern, pressure, slug velocity and gas-liquid distribution characteristics. In the meantime, the multi-fluid volume of fluid (VOF) model was used in the CFD simulations, and the simulation results were compared against the experimental results for verification. The results showed that the void fraction is highest at the inlet and lowest at the middle position, and the pressure and flow velocity at the extrados were higher than those at the intrados of the elbow. With the increase of the superficial liquid velocity and gas velocity, the number of bubbles accumulated inside the horizontal elbow increased, the slug flow liquid film velocity of the horizontal elbow increased, and the secondary flow phenomenon weakened.

Experimental Design of Nature-Based-Solution Considering the Interactions between Submerged Vegetation and Pile Group on the Structure of the River Flow on Sand Beds

Designing correct engineering infrastructures to reduce land degradation processes and considering natural elements to achieve this goal are key to correctly managing potential natural hazards affecting human activities and natural ecosystems. This research investigated the scour depth and velocity vectors around bridge piles with and without upstream vegetation protection. A Doppler velocity meter was used to measure velocity components in a channel 90 cm wide, 16 m long, and 60 cm high. Variable parameters were the number of bridge piles, the height, density, and width of vegetation upstream, as well as the distance between bridge piles. Using a triple pile group with a distance between piles of 10 cm and overall vegetation across the channel, the depth of the scour hole upstream of the first pile decreased by 40% compared to the single pile with no vegetation. This result shows the significant impact of using vegetation and pile groups to reduce scour around piles. Lower vertical velocity gradients, more consistent velocity vectors, reducing the downstream flow range, and restraining horseshoe vortexes and wake vortices were observed in utilizing vegetation. We confirmed that vegetation is an essential factor in changing the flow, transportation of sediment, and conserving ecological services in rivers.

Experiments on turbulence from colliding ice floes

Increased knowledge about energy dissipation processes around colliding ice floes is important for improved understanding of atmosphere-ice-ocean energy transfer, wave propagation through sea ice, and the polar climates. The aim of this study is to obtain such information by investigating colliding ice floe dynamics in a large-scale experiment and directly measuring and quantifying the turbulent kinetic energy (TKE). The field work was carried out at Van Mijen Fjord on Svalbard, where a 3 × 4 m ice floe was sawed out in the fast ice. Ice floe collisions and relative water–ice motion were generated by pulling the ice floe back and forth in an oscillatory manner in a 4 × 6 m pool, using two electrical winches. Ice floe motion was measured with a range meter and accelerometers, and the water turbulence was measured acoustically with Doppler velocimeters and optically with a remotely operated vehicle and bubbles as tracers. Turbulent kinetic energy spectra were found to contain an inertial subrange where energy was cascading at a rate proportional to the −5/3 power law. The TKE dissipation rate was found to decrease exponentially with depth. The total TKE dissipation rate was estimated by assuming that turbulence was induced over an area corresponding to the surface of the floe. The results suggest that approximately 37% and 8% of the input power from the winches were dissipated in turbulence and absorbed in the collisions, respectively, which experimentally confirms that energy dissipation by induced turbulent water motion is an important mechanism for colliding ice floe fields.

Синтез дискретных полосовых и режекторных фильтров методом инвариантных дифференциальных уравнений.

Introduction – The issue of constructing discrete band-pass and notch filters using differential equations of continuous analog filters of low and high frequencies is considered. Purpose – Development of a technique for the synthesis of tunable band-pass and notch filters with a constant width of the amplitude-frequency characteristics, regardless of the filter tuning frequency. Setting the task – Based on the invariant differential equations of continuous analog filters of low and high frequencies, find the weight coefficients of the difference equations that determine the operation of discrete bandpass and notch filters that have a constant width of amplitude-frequency characteristics under conditions of variable filter tuning frequency. Method – The synthesis is based on the presentation of the mathematical frequency transfer function of the filter separately in the region of positive and negative frequencies, for each of which a bilinear z-transform is applied shifted to the tuning frequency of the selected region. Results – Difference equations of discrete filters are obtained from the given differential equations of continuous analog filters of low and high frequencies. Frequency-shifted bilinear z-transformations are presented. Transfer functions in the z-plane are obtained separately for the regions of the frequency transfer function of the filter located in the ranges of positive and negative frequencies. By summing the transfer functions in the z-plane for the regions of positive and negative frequencies and multiplying these transfer functions, the resulting transfer functions in the z-plane are obtained for discrete bandpass and notch filters. By passing from the z-plane to the jω, expressions for the frequency transfer functions of the synthesized band-pass and notch filters are obtained. The calculation of their amplitude-frequency characteristics has been made. It is shown that the width of the amplitude-frequency characteristics of the synthesized filters remains constant when the filter tuning frequency is changed. Practical relevance – The developed technique for the synthesis of tunable real discrete band-pass and notch filters with a constant frequency response width based on invariant differential equations of continuous analog filters will be very useful in the construction of adaptive systems and signal processing devices, such as signal detection and filtering systems, Doppler velocity meters, selection systems moving targets.

Doppler velocimeter and vibrometer FMCW LiDAR with Si photonic crystal beam scanner.

In this paper, we propose and demonstrate a frequency-modulated continuous-wave light detection and ranging (LiDAR) with a Si photonic crystal beam scanner, simultaneously enabling scanning laser Doppler measurements. This nonmechanical solid-state device can reduce the size of conventional scanning laser Doppler vibrometers, making LiDAR a multimodal imaging sensor, which can measure the distributions of distance, velocity, and vibration frequency. We fabricated this device using Si photonics process and confirmed the expected operations. Distance and velocity resolutions were less than 15 mm and 19 mm/s, respectively. The detection limit of the vibration amplitude determined by the signal-to-noise ratio was 2.5 nm.

Application of Stage-Fall-Discharge Rating Curves to a Reservoir Based on Acoustic Doppler Velocity Meter Measurement Data

The applicability of the stage-fall-discharge (SFD) method in combination with acoustic Doppler velocity meter (ADVM) data, upstream of a hydraulic structure, specifically, the Sejong-weir located in the Geum River, Korea, was examined. We developed three rating curves: a conventional simple rating curve with the data measured using an acoustic Doppler current profiler (ADCP) and floating objects, an SFD rating curve with the data measured using the ADCP and floating objects, and an SFD rating curve with the data measured using an ADVM. Because of the gate operation effect, every rating curve involved many uncertainties under 1000 m3/s (3.13 m2/s, specific discharge). In terms of the hydrograph reconstruction, compared with the conventional simple rating curve, the SFD developed using ADVM data exhibited a higher agreement with the measured data in terms of the pattern. Furthermore, the measured discharge over 1000 m3/s primarily ranged between 97.5% and 2.5% in the graph comparing the ratio of the median and observed discharge. Based on this experiment, it is confirmed that the SFD rating curve with data to represent the backwater effect, such as ADVM data, can reduce the uncertainties induced by the typical rating curve

Deep-sea <i>in-situ</i> laser Doppler velocity measurement system

A set of 4000-meter laser Doppler hydrothermal velocity measurement prototype suitable for deep sea <i>in-situ</i> measurement is developed in this work. In the system, an integrated design is adopted. The system is composed of a light source module, an optical module, and a Doppler signal processing module. The system is encapsulated in a pressure chamber with <i>L</i>500 mm × <i>Φ</i>205 mm to form an integrated optical measuring probe. An optical path of two-beam laser Doppler velocity measurement with strong local oscillator is proposed. The prototype is used to measure the simulated velocity in the laboratory. The measurement range is 0.01–10 m/s, and the flow velocity measurement resolution is 0.001 m/s. The experimental results preliminarily prove the feasibility of the laser Doppler velocity measurement system. After that, a withstanding voltage test on the system is conducted at the Qingdao Deep Sea Base, and the system obtains a normal signal under a high pressure of 40 MPa. A speed comparison measurement is carried out at the China Institute of Water Resources and Hydropower Research. In a low speed range from 0.01 m/s to 0.2 m/s, comparing with the acoustic Doppler velocity meter, the maximum measurement relative error is –9.43%. In a high speed range from 0.8 m/s to 9.6 m/s, comparing with the nozzle standard flow rate system, the maximum relative measurement error is –1.65%. The prototype system is tested in a shallow sea in Lingshui, Hainan. The sinking speed of the prototype system that sinks together with a crane down to a water depth of 50 m, and the towing speed of the system together with the ship at a depth of 2 m are tested. The test proves that the prototype system works normally in a shallow sea environment.

Schmidt ST-EKF for Autonomous Land Vehicle SINS/ODO/LDV Integrated Navigation

Autonomous land navigation has been studied extensively in recent years to improve vehicle location accuracy in the satellite-denial environment. However, many previous studies of strapdown inertial navigation system/odometer (SINS/ODO) integrated navigation mainly focus on the horizontal location and neglect the height positioning since the troublesome problem of vertical channel divergency without extra height information assistance. In contrast, this article considered both horizontal and vertical positioning accuracy by SINS/ODO/laser doppler velocimeter (LDV)-based integration framework and proposed a novel algorithm named Schmidt ST-EKF which takes advantage of both ST-EKF’s consistency by nonlinear error definition and Schmidt filter’s improvement on system observability. Detailed system equations and observation equations of Schmidt ST-EKF-based SINS/ODO/LDV integrated navigation are derived and followed by concrete experiment results, which showed that the SINS/ODO/LDV integration method had better horizontal location accuracy than SINS/ODO integration by 35% and SINS/LDV integration by 26% and that applying Schmidt ST-EKF could efficiently reduce height positioning error. A further experiment about the correlating time of pitch mounting angle’s influence is conducted and revealed that the Schmidt ST-EKF is more robust than ST-EKF. Consequently, the algorithm proposed in this article for SINS/ODO/LDV has strong engineering applicability in the vast class of land vehicle applications.

Experimental Study and Fatigue Analysis of Vortex-Induced Vibration of Umbilical Cable Considering Internal Friction

In order to investigate the effect of internal friction of umbilical cable on its vortex-induced vibration (VIV) responses, the experimental study on VIV of bond umbilical cable (BUC) and un-bond umbilical cable (UBUC) was carried out in an experimental tank. A current generator in the laboratory simulated the uniform current, and the current velocities were observed in real time by using a Doppler Velocimeter. In addition, different sizes of top tension were applied to the umbilical cable model. The VIV responses of the umbilical cable model were measured by using Fiber Bragg grating (FBG) strain sensors. The displacement responses of umbilical cable model were reconstructed based on the experimental strain data processed by modal superposition method. In this paper, the traveling wave characteristics, the spatial-temporal distribution characteristics of frequency and fatigue damage of the BUC and UBUC under VIV are studied. The experimental results show that there are obvious differences between BUC and UBUC in the response characteristics of VIV. The UBUC appears the traveling wave sooner than BUC, but its standing wave characteristics are more obvious than those of BUC at high velocities. Compared with BUC, the spatial-temporal distribution of UBUC frequencies appears wide-band distribution sooner, but has narrower bandwidth in the “lock-in” state. The level of fatigue damage of BUC was approximately the same as that of UBUC.

СТВОРЕННЯ БЛОКУ ВИМІРУ ЧАСТОТИ ДЛЯ ДОППЛЕРІВСЬКОГО УЛЬТРАЗВУКОВОГО ВИТРАТОМІРА

One of the indicators of human hemodynamics is the rate of blood flow in the blood vessels. The rate of blood flow depends on the frequency of heart muscle contractions, the amount and quality of blood, vascular size, blood pressure, age and genetic features of the body. At present, the method of ultrasound dopplerography has been widely used in diagnosis of widespread use. But since the signal received by the Doppler velocity meter is a spectrum of frequencies, the question of creating a frequency measurement unit for quantifying the state of hemodynamics is relevant. This article describ esthecreation and simulation off requency measurement unit that operatesat frequencies from 200 to 20,000 Hzvoltageby 15 V, valuesrangefrom 6 to 1.25 V.

Power-Efficient Algorithm of Controlling the Engine Thrust at the Final Phase of Soft Moon Landing

The theme is topical because of the ongoing Russian lunar program. Four more launches of Luna-25 to Luna-28 are planned for the next several years. Only in 8 out of 14 cases, the soft Moon landing was provided. This fact prompts researchers to seek after new ways of solving this problem. The article deals with a power-efficient control algorithm that controls landing engine thrust at the final phase of spacecraft landing from a given hovering point to the point of contact with the Moon’s surface. Initially not supposed to be used for solution of terminal control tasks, the power-efficient algorithm can be applied here, which can be explained by availability of an auxiliary system in it that provides reaching specified motion parameters within a specified period. At the final phase of soft Moon landing, the proposed algorithm treats the spacecraft as a material point that moves by the attractive force of the Moon and the opposite vertical force of the landing engine thrust. It is supposed that to form the thrust the vertical velocity is measured by a Doppler velocimeter and the altitude by a multibeam vertical-building radio altimeter, throughout the whole motion interval. W hen calculating the parameters of spacecraft motion under the conditions of the Moon’s gravitational field at the final phase of spacecraft contact with the Moon’s surface by the mentioned algorithm, there is a possibility of some overcorrection, which is inadmissible. To exclude it, a well-known approach is used when the motion is considered on the assumption of absence of the Moon’s gravitational field. In this case the control will be implemented without overcorrection, but to obtain the actual engine thrust it is necessary to add the force opposite to the direction of the Moon’s attraction force, acting upon the spacecraft, to the algorithm-generated signal at every control step. The author has mathematically modeled the algorithm. The results of modeling proved the appropriateness of the problem statement and allow finding the boundary of the algorithm applicability: to exclude reversing of the landing engine thrust the initial spacecraft hovering altitude should be less than 647 m. The algorithm can also be used for controlling automatic landing of vertical takeoff aircraft.

Effect of Physical Methods of Lymphatic Drainage on Postexercise Recovery of Mixed Martial Arts Athletes.

Physical methods are reported to be important for accelerating skeletal muscle regeneration, decreasing muscle soreness, and shortening of the recovery time. The aim of the study was to assess the effect of the physical methods of lymphatic drainage (PMLD) such as manual lymphatic drainage (MLD), the Bodyflow (BF) therapy, and lymphatic drainage by deep oscillation (DO) on postexercise regeneration of the forearm muscles of mixed martial arts (MMA) athletes. Eighty MMA athletes aged 27.5 ± 6.4 years were allocated to 4 groups: MLD, the BF device, DO therapy, and the control group. Blood flow velocity in the cephalic vein was measured with the ultrasound Doppler velocity meter. Maximal strength of the forearm muscles (Fmax), muscle tissue tension, pain threshold, blood lactate concentration (LA), and activity of creatine kinase were measured in all groups at rest, after the muscle fatigue test (post-ex) and then 20 minutes, 24, and 48 hours after the application of PMLD. The muscle fatigue test reduced Fmax in all subjects, but in the groups receiving MLD, DO, and BF significantly higher Fmax was observed at recovery compared with post-ex values. The application of MDL reduced the postexercise blood LA and postexercise muscle tension. The lymphatic drainage methods, whether manual or using electro-stimulation and DO, improve postexercise regeneration of the forearm muscles of MMA athletes. The methods can be an important element of therapeutic management focused on optimizing training effects and reducing the risk of injuries of the combat sports athletes.

Protecting bridge piers against local scour using a flow-diversion structure

Previous studies indicate that local scour is a leading cause of most waterway bridge failures during flood events. Using armouring countermeasures such as riprap and gabions is a conventional way of reducing scour around bridge piers, but is very costly and time consuming. As an alternative, a flow-diversion structure is proposed that has a triangular prismatic shape with dimensions much smaller than the actual pier and should be installed upstream of the pier. To assess its performance, experiments were conducted under clear-water scour conditions. After achieving equilibrium bed conditions, the bed profile was measured and the maximum scour depth and volume of the scour hole were determined for each experimental test. The results indicated that the clear distance between the pier and the countermeasure to achieve the maximum reduction in local scour was 1·5 times the pier diameter. For this condition, the proposed countermeasure reduced the maximum scour depth by 38% and the volume of the scour hole was decreased by around 61%. To determine the influence of the countermeasure on flow field around the pier, three-dimensional velocity components were measured at grid points using a micro-acoustic Doppler velocity meter. Analysis of the results indicated that the proposed structure could change both the magnitude and direction of the velocity components upstream of the pier and consequently induce a significant reduction in local scour depth and volume around the pier.

Design of a multiple self-mixing interferometer for a fiber ring laser.

In this Letter, a novel multiple self-mixing interferometer for a fiber ring laser (FRL) is designed by introducing a circular feedback cavity. A system model is established based on an injection-seeded erbium-doped FRL proposed by Dragic. Owing to the reflection of the collimating lens, the multiplied fringes have different depths, which shows two Doppler frequencies in the spectrum of the self-mixing signal. A double-peak frequency identification algorithm is proposed to extract the Doppler frequency from the unique signal. This technique has the potential to improve the accuracy of fiber self-mixing measurement systems, particularly in Doppler velocimeters.

Integration of polarization-multiplexing and phase-shifting in nanometric two dimensional self-mixing measurement.

Integration of phase manipulation and polarization multiplexing was introduced to self-mixing interferometry (SMI) for high-sensitive measurement. Light polarizations were used to increase measuring path number and predict manifold merits for potential applications. Laser source was studied as a microwave-photonic resonator optically-injected by double reflected lights on a two-feedback-factor analytical model. Independent external paths exploited magnesium-oxide doped lithium niobate crystals at perpendicular polarizations to transfer interferometric phases into amplitudes of harmonics. Theoretical resolutions reached angstrom level. By integrating two techniques, this SMI outperformed the conventional single-path SMIs by simultaneous dual-targets measurement on single laser tube with high sensitivity and low speckle noise. In experimental demonstration, by nonlinear filtering method, a custom-made phase-resolved algorithm real-time figured out instantaneous two-dimensional displacements with nanometer resolution. Experimental comparisons to lock-in technique and a commercial Ploytec-5000 laser Doppler velocity meter validated this two-path SMI in micron range without optical cross-talk. Moreover, accuracy subjected to slewing rates of crystals could be flexibly adjusted.

Carrier-separating demodulation of phase shifting self-mixing interferometry

A carrier separating method associated with noise-elimination had been introduced into a sinusoidal phase-shifting self-mixing interferometer. The conventional sinusoidal phase shifting self-mixing interferometry was developed into a more competitive instrument with high computing efficiency and nanometer accuracy of λ/100 in dynamical vibration measurement. The high slew rate electro-optic modulator induced a sinusoidal phase carrier with ultralow insertion loss in this paper. In order to extract phase-shift quickly and precisely, this paper employed the carrier-separating to directly generate quadrature signals without complicated frequency domain transforms. Moreover, most noises were evaluated and suppressed by a noise-elimination technology synthesizing empirical mode decomposition with wavelet transform. The overall laser system was described and inherent advantages such as high computational efficiency and decreased nonlinear errors of the established system were demonstrated. The experiment implemented on a high precision PZT (positioning accuracy was better than 1nm) and compared with laser Doppler velocity meter. The good agreement of two instruments shown that the short-term resolution had improved from 10nm to 1.5nm in dynamic vibration measurement with reduced time expense. This was useful in precision measurement to improve the SMI with same sampling rate. The proposed signal processing was performed in pure time-domain requiring no preprocessing electronic circuits.

Denoising and despiking ADV velocity and salinity concentration data in turbulent stratified flows

Due to the presence of noise and spikes in velocity measurements of turbulent flow fields, understanding the flow pattern may be seriously affected by the spurious values for zones where certain flow behaviour is not necessarily expected. In a series of laboratory experiments the velocity data recorded, using Acoustic Doppler Velocity meters (ADVs), and the salinity measurements were noticeably noisy. In despiking and denoising the velocity data a linear correlation algorithm was established, which successfully lowered the noise levels and removed the spikes. For the assessment of the method, an autoregressive model was used to generate a clean velocity signal. The spikes were generated with a uniformly random time index and a Gaussian distributed value, where White Gaussian noise was added to this simulated signal. Assessment was also undertaken on the signals generated using a three-dimensional numerical model. To enhance the comprehension of the flow field, an interpolation method for producing the missing data has also been developed, which may be deployed to increase the sampling frequency, or to produce data for the spatial domain at locations which are not included in the measurements. For salinity a different strategy was applied where a moving average procedure was carried out, as the data did not suffer from spikes and exhibited almost a constant band of noisy fluctuations.

Enhancing PIV image and fractal descriptor for velocity and shear stresses propagation around a circular pier

In this study, the fractal dimensions of velocity fluctuations and the Reynolds shear stresses propagation for flow around a circular bridge pier are presented. In the study reported herein, the fractal dimension of velocity fluctuations (u′, v′, w′) and the Reynolds shear stresses (u′v′ and u′w′) of flow around a bridge pier were computed using a Fractal Interpolation Function (FIF) algorithm. The velocity fluctuations of flow along a horizontal plane above the bed were measured using Acoustic Doppler Velocity meter (ADV) and Particle Image Velocimetry (PIV). The PIV is a powerful technique which enables us to attain high resolution spatial and temporal information of turbulent flow using instantaneous time snapshots. In this study, PIV was used for detection of high resolution fractal scaling around a bridge pier. The results showed that the fractal dimension of flow fluctuated significantly in the longitudinal and transverse directions in the vicinity of the pier. It was also found that the fractal dimension of velocity fluctuations and shear stresses increased rapidly at vicinity of pier at downstream whereas it remained approximately unchanged far downstream of the pier. The higher value of fractal dimension was found at a distance equal to one times of the pier diameter in the back of the pier. Furthermore, the average fractal dimension for the streamwise and transverse velocity fluctuations decreased from the centreline to the side wall of the flume. Finally, the results from ADV measurement were consistent with the result from PIV, therefore, the ADV enables to detect turbulent characteristics of flow around a circular bridge pier.