Ow Characteristics Research Articles

Оценка кинематической структуры потока за колодцем заглубленного типа в нижнем бьефе водопропусных сооружений АПК

The purpose of the investigation is to study the operating conditions of the downstream of the low-pressure conjugation and water passageway structures of the reclamation complex of the agro-industrial complex (AIC) in relation to the structural scheme of culvert sections operating in the conditions of the conjugation of the pools by the type of a submerged jet in the presence of a deep, relatively short stilling well. A brief description of the laboratory installation, the measuring equipment used to record turbulent fl ow characteristics and the methodology for performing model studies is given. The results are given on fi nding and studying rational downstream structures and devices (hearth, baffl es, apron) taking into account pulsating fl ow effects on the fastening elements. The fl ow modes behind the culvert structure and spillway dam with a deep well have been established, calculated dependences are given to determine its optimal parameters and assess the average and pulsation components of pressure on the main elements of the downstream devices. On the model operating at the Reynolds numbers over 10000 and Froude numbers in the compressed section from 20 to 120, a design was chosen that provides the greatest energy baffl e effect at the angle of the turbulent jet entry into the well varying within 50°…70°, which includes blocks in addition to the deep short well. This made it possible to analyze the kinematic structure of the fl ow and reveal the intense attenuation of the pulsation component of the fl ow velocities and pressures along the length of the outlet channel by about 20% compared to a jump well of simple outlines, and a decrease in the planned irregularity of the diagrams. All this together confi rmed the effi ciency of the structure on the sloping sections of the reclamation network for the structures with a specifi c fl ow rate in the range of 0.15…5.5 m2 /s. As a result of the research carried out, the design of the device and downstream anchorage has been improved providing the necessary reliability of its operation.

ОПТИМИЗАЦИЯ КОНСТРУКТИВНО-РЕЖИМНЫХ ПАРАМЕТРОВ ГИДРОЦИКЛОНА С УЧЕТОМ НАТУРНЫХ ИССЛЕДОВАНИЙ

Cylindrical-conical pressure hydrocyclones are characterized by high productivity and efficiency indicators of water treatment from mechanical impurities at a relatively small size and cost, low resource costs for operation, which makes their use promising as a water treatment unit in the circulating water distribution systems of domestic and foreign industry. The purpose of the research is development of the construction of a filtering hydrocyclone and assessment of the impact of the fl ow characteristics and size of the sand pipe on the separative power of the apparatus in the process of water teratment from mechanical impurities. The presented design of the hydrocyclone apparatus with a filter drain pipe allows to increase water treatment rates from mechanical impurities including by trapping the smallest suspensions. As a result of experimental research of the effect of the flow characteristics and size of the sand pipe on the separative power of the apparatus, the technological and construction parameters of the PH-100 hydrocyclone with various versions of the drain pipe providing maximum efficiency of water treatment from mechanical impurities have been established. The graphoanalytic solution of the obtained regression equations has allowed us to establish that a hydrocyclone with a solid side wall drain pipe provides the maximum degree of water treatment from mechanical impurities at the level of 85.4% at a flow rate of 6.5 m3/h and a 12 mm diameter of the sand pipe. Replacing the standard construction drain pipe with a filtering side surface drain pipe increases the integral degree of water treatment from mechanical impurities to 96.4% with the same flow parameters and diameter of the sand pipe.

Heat Exchange in Unsaturated Porous Media with Heat Dependent Water Flow

We discuss the heat and mass transport in unsaturated-saturated porous mediaincluding heat exchange between inltrated water and matrix. We include the thermal inuenceon hydraulic permeability and on the water expansion which changes the water saturation.This consequently inuences the hydraulic permeability.Numerical modelling includes the direct and inverse solution of the problem, where model parametersare determined. Numerical experiments require only simple input/output measurementsof suitable ow characteristics in laboratory conditions with 3D cylindrical samples.The ow model is based on Richard's strongly non-linear parabolic equation based on empiricalvan Genuchten's capillary-pressure model. The transport includes longitudinal and transversaldispersion.

DESIGN AND STUDY OF EXCHANGERS WITH PRESSURE GRADIENT HEAT INTENSIFIERS

This paper is presented the numerical study of local heat transfer in the turbulent boundary layer with longitudinal pressure gradient. The study is based to free software with open source code (Salome and Code_Saturne) has been based by RANS approach and empirical models of turbulence. Validation of mathematical models and software is based by collation numerical results with the results of experimental study of fl ow characteristics in a turbulent boundary layer of longitudinal pressure gradient and high turbulence intensity (Epik E. Ya., NASc of Ukraine). The validation had a high qualitative coincidence of the fl ow characteristics determined as a result of the simulation with experimental data. We designed two constructive schemes of heat exchangers for air. This study presents a calculation plan for these heat exchangers. Results of the study are showed that the use of gradient heat exchange intensifi ers leads to an increase in the heat transfer coeffi cient from air to 17 %.

Flow characteristics of intermittent rivers in Slovakia

Abstract Flow characteristics of intermittent rivers in Slovakia. Intermittent rivers are rivers that cease to fl ow, i.e. temporary, ephemeral, seasonal, and episodic rivers. Analysis of hydrological regime of such rivers is pivotal in assessment of water resources because changes in fl ow characteristics of such rivers may affect neighboring catchments or the entire region through changes in water supply reservoirs such as lakes, wetlands and mosses. Recently, an increasing number of intermittent rivers and ephemeral streams (IRES) and an elongation of the zero- -fl ow events has been observed in Europe due to climatic changes and anthropogenic influence. Intermittent rives in Slovakia were studied in the paper using statistical methods. The characteristics of the zero-fl ow period, of duration of the longest annual zero-fl ow event and of timing of such events were derived. The circular statistics were helpful in recognition of the dates of occurrence of such events. The comparative analysis between catchments was performed. The variability in precipitation and evapotranspiration and the increasing temperature were identified as the possible drivers of the fl ow intermittence in these catchments. The research was performed within the COST Action SMIRES (Science and Management of Intermittent Rivers & Ephemeral Streams).

Financial Feasibility of Investing in Smallholder Cow-Calf Cooperatives in Baluran National Park

Livestock grazing is a major driver of human-wildlife confl ict in conservation areas. Currently, it is estimated that 3000 heads of cattle illegally grazing within Baluran National Park (BNP) in East Java. The recent research has suggested the potential of livestock system intensifi cation to reduce land-use and conflict through conservation priorities. The research goal was to investigate the fi nancial feasibility of starting intensive cow-calf cooperatives by smallholders in the BNP area. Data were collected using Farm surveys in a Criterion sampling design. Optimal herd management plans were generated using whole farm Linear Programming and fi nancial feasibility was assessed using Discounted cash-flow analysis and debt-servicing capabilities. Investment lifetime was set at 15 years and four alternative varieties of cattle were taken from Bali, Peranakan Ongole, Limousin and Simmental. Results show that investing in all varieties represents a positive investment opportunity. Bali cattle obtaining the highest NPV ($53.769), IRR (14,25%) and B/C ratio (1,13). Farmer income can be increased by 163% by combining additional Off-farm labor. However, debt servicing capabilities of cow-calf cooperative activities showed that the loan principal can only be repaid in the 10th year instead of the maximum eight years set by the government cow-calf credit scheme. We urge the government to reconsider either the grace period or the repayment time of the credit scheme to better fit the cash-fl ow characteristics of cow-calf enterprises.

MATHEMATICAL MODELS OF COGENERATION STEAM TURBINES BASED ON EXPERIMENTAL CHARACTERISTICS OF TURBINE STAGES AND COMPARTMENTS

The article covers approaches to building the mathematical models of cogeneration steam turbine units. The objective of this work is the development, justifi cation and practical implementation of methods of mathematical modeling of cogeneration steam turbines for solving research problems and improving the energy effi ciency of the CHP. The use of normative characteristics to solve these tasks, which require the calculation of variable modes, in most cases turns out to be unjustifi ed, due to a number of their signifi cant shortcomings. It is shown that the application of the developed mathematical models based on experimentally determined fl ow and power characteristics allows to solve various practical tasks arising during operation. We have given an example of constructing a computational mathematical model of a T-50-12.8 type turbine. The method of construction of this model is described, which consists of a large number of nonlinear equations (over 50), and an enlarged block diagram of calculations for this turbine (using the modernized Newton method with a step change of the iteration process in several variables) is provided. The method of calculating an arbitrary turbine compartment or a stage using some experimental fl ow and power characteristics is given as part of the general algorithm. A method for calculating the LPH-1 regenerative heater is also given as an example. It is shown how similar models of other equipment can be developed on the basis of the described mathematical model. The article provides examples of the use of mathematical models of turbines for solving problems of determining the most economical and safe operating modes and preventing ineffi cient solutions. The obtained results allow to determine the optimal operating modes of real CHP equipment and calculating their absolute and comparative energy efficiency.

MULTIDIMENSIONAL OPEN SYSTEM FOR VALVELESS PUMPING

In this study, we present a multidimensional open system for valveless pumping (VP). This system consists of an elastic tube connected to two open tanks filled with a fluid under gravity. The two-dimensional elastic tube model is constructed based on the immersed boundary method, and the tank model is governed by a system of ordinary differential equations based on the work-energy principle. The flows into and out of the elastic tube are modeled in terms of the source/sink patches inside the tube. The fluid dynamics of this system is generated by the periodic compress-and-release action applied to an asymmetric region of the elastic tube. We have developed an algorithm to couple these partial differential equations and ordinary differential equations using the pressure-flow relationship and the linearity of the discretized Navier-Stokes equations. We have observed the most important feature of VP, namely, the existence of a unidirectional net flow in the system. Our computations are focused on the factors that strongly influence the occurrence of unidirectional flows, for example, the frequency, compression duration, and location of pumping. Based on these investigations, some case studies are performed to observe the details of the ow features.

Derivation of consolidation partial differential equations with non-linear fl ow characteristics on organic soil example

Abstract Derivation of consolidation partial differential equations with non-linear flow characteristics on organic soil example. Derivation of consolidation partial differential equation with non-linear flow characteristics is proposed. The non-linear flow characteristics are obtained from flow-pump test on organic soil and described with empirical relationship. Several reasons were crucial to perform tests on organic soil. Firstly organic soils are very compressible, so that results in high permeability changes. Even with small stresses organic soil deforms a lot. Secondly road embankments, flood control levees, dykes and dams are very often located on organic soil, so it is important to model deformations under these constructions. Thus to model consolidation process in soft organic soil one should consider as follows: physical and mechanical properties, non-linear stress-strain relationship, non-linear flow characteristics, and creep strains. This paper is focused mainly on non-linear flow characteristics that change with porosity and hydraulic gradient variations.

Multi-Objective Optimization of a Fluid StructureInteraction Benchmarking

The integration and application of a new multi-objective tabu search optimization algorithm for Fluid Structure Interaction (FSI) problems are presented. The aim is to enhance the computational design process for real world applications and to achieve higher performance of the whole system for the four considered objectives. The described system combines the optimizer with a well established FSI solver which is based on the fully implicit, monolithic formuFlation of the problem in the Arbitrary Lagrangian-Eulerian FEM approach. The proposed solver resolves the proposed uid-structure interaction benchmark which describes the self-induced elastic deformation of a beam attached to a cylinder in laminar channel ow. The optimized ow characteristics of the aforementioned geometrical arrangement illustrate the performance of the system in two dimensions. Special emphasis is given to the analysis of the simulation package, which is of high accuracy and is the core of application. The design process identifies the best combination of ow features for optimal system behavior and the most important objectives. In addition, the presented methodology has the potential to run in parallel, which will significantly speed-up the elapsed time. Finite Element Method (FEM), Fluid-Structure Interaction (FSI), Multi-Ojective Tabu search (MOTS2). Copyright © 2013 Tech Science Press.

Active and Passive Flow Control of Turbomachines

Turbomachines are used in a wide range of applications. Increasing the efficiency and operating range of turbomachines reduces fuel consumption of gas turbine power plants and other applications. Over the years, many attempts have been made to achieve these objectives. e present special issue addresses these goals with special emphasis on active and passive �ow control techniques. is special issue compiles 7 original research articles that describe active and passive �ow control techniques applied to different types of turbomachines. e theme for this special issue is set by J. P. Gostelow et al. ey describe various types of vortices encountered in a transonic turbine nozzle blade passage. Active and passive control of these vortices is essential to improve the performance of turbines. ere are two more papers on control of turbine �ows. e paper by R. Da Soghe et al. describes aerothermal analysis of a turbine casing impingement cooling system. T. Matsunuma and T. Segawa systematically varied the input voltage of plasma actuators to reattach the simulated boundary layer on the suction surface of a turbine at a low Reynolds number. e low-pressure turbine of aircra gas turbine power plants operating at high altitudes operates at low Reynolds numbers. Losses in turbines operating at low Reynolds numbers increase rapidly due to large separation occurring on the suction surfaces of the turbine blades. Many researchers used dielectric barrier discharge (DBD) plasma actuators to actively control �ow separation, tip clearance �ows, and so forth in turbines and other turbomachinery components. e present paper by T. Matsunuma and T. Segawa is a great addition to the available data that addresses the effects of input voltage to plasma actuators on �ow control effectiveness. Two papers describe active and passive �ow control techniques applied to centrifugal compressors. A. Marsan et al. numerically investigated boundary layer suction technique applied to the radial diffuser of a transonic centrifugal compressor. ey had presented an efficient control technique, which used a suction mass �ow rate of 0.1% of global mass �ow to increase the compressor operating range by 40%. T. Hirano et al. experimentally investigated a passive nozzle injection system to control surge and rotating stall in high speed centrifugal compressors. ey demonstrated optimum circumferential position of the injection nozzle. S. Kyparissis and D. Margaris tested impellers with three different leading edge angles to optimize the leading edge angle to reduce cavitation development and enhance the performance of a centrifugal pump. Active and passive �ow control techniques are being extensively investigated in the primary components of turbomachinery. However to further improve the performance of turbomachinery, active and passive �ow control techniques need to be applied to secondary components of turbomachines, such as seals. e last paper of the special issue by M. �hang et al. addresses leakage �ow characteristics of seals used in reactor coolant pumps. ey had numerically shown that helical groove seal controls the leakage along the front surface of the impeller face due to its higher resistance than the circumferential grooved seal. It is hoped that this special issue will provide useful information to wide readership from academia, industry and research establishments and inspire new and more efficient control techniques.

Effect of the Transient Nature of Flow on Annular Parachute Drag Prediction

The aerodynamics of parachute systems are highly unsteady, resulting from separated ∞ows, vortex shedding, etc., caused by complex interactions between a ∞exible canopy and its payload. However, when dynamically permitted, the ∞owflelds and resulting surface forces have often been approximated using the assumptions and characteristics of rigid bodies and steady-state simulations. For example, results from steady-state simulations have been used successfully to assist the determination of parachute loading and trajectory. They have even been used in the estimation of peak drag and canopy fllling times sustained by in∞ating parachutes. This paper compares ∞ow characteristics and canopy drag obtained from solving the steady-state equations with those calculated with the unsteady equations, using a Reynolds Reynolds-Averaged Navier Stokes ∞ow solver on a rigid concentric annular parachute geometry comprised of two concentric fabric rings. The rings have unequal diameters and are vertically ofiset. Under load, the in∞ated rings not only yield a canopy that is highly porous but one that is characterized by high drag, a result of the cambered proflle formed by the billowing of the rings. The simulations have been performed at two Reynolds numbers of 8:03 ¢ 10 6 and 10:04 ¢ 10 6 . In particular, drag forces and wake characteristics observed in the steady simulations are compared to the unsteady simulations in order to judge the ability of the steady-state equations to capture the behavior noted in the transient cases. Results also include velocity, vorticity, and turbulence contours to help clarify the ∞ow physics resulting from steady and unsteady simulations.

Towards optimization of spacer geometrical characteristics for spiral wound membrane modules

Key parameters in the design of spiral wound elements are the geometrical characteristics of net-type spacers at the feed-flow channels, which greatly influence the transport phenomena therein and the overall operation of these modules. Recent results from a comprehensive theoretical and experimental study, on the fl ow characteristics and mass transfer in narrow channels with spacers, summarized in this paper, provide basic information that enables optimization of spacer characteristics. The new results include correlations of pressure drop and of average mass transfer rates to the wall as well as distributions of local shear stress and mass transfer, as a function of Reynolds and Schmidt number and of spacer geometry. An assessment of spacers, based on the above results, indicate trends, regarding geometric parameter values, leading to improved membrane element performance. Numerical results are also presented of an example, involving a single element in a RO seawater desalination plant, which demonstra...

Model of turbo-charging system of traction diesel engine

This paper presents empirical-mathematical model of turbo-charging for the Diesel engine with sequential turbocharging. The model is based on application of the SW 680 engine characteristics obtained on the basis of average parameters of a cycle as well as fl ow characteristics of turbochargers, for the description of which the methods of multiple regression have been used. The conditions of the turbocharger co-operation with the traction engine have been taken into account by means of pulsation coeffi cients, which ensures suffi cient convergence of numerical calculations with the results of experimental testing.

Predictability of Lagrangian particle trajectories: Effects of smoothing of the underlying Eulerian flow

The increasing realism of ocean circulation models is leading to an increasing use of Eulerian models as a basis to compute transport properties and to predict the fate of Lagrangian quantities. There exists, however, a signie cant gap between the spatial scales of model resolution and that of forces acting on Lagrangian particles. These scales may contain high vorticity coherent structures that are not resolved due to computational issues and/or missing dynamics and are typically suppressed by smoothing operators. In this study, the impact of smoothing of the Eulerian e elds on the predictability of Lagrangian particles is e rst investigated by conducting twin experiments that involve release of clusters of synthetic Lagrangian particles into “ true” (unmodie ed) and “ model” (smoothed) Eulerian e elds, which are generated by a QG model with a e ow e eld consisting of many turbulent coherent structures. The Lagrangian errors induced by Eulerian smoothing errors are quantie ed by using two metrics, the difference between the centers of mass (CM) of particle clusters, r, and the difference between scattering of particles around the center of mass, s. The results show that the smoothing has a strong effect on the CM behavior, while the scatter around it is only partially affected. The QG results are then compared to results obtained from a multi-particle Lagrangian Stochastic Model (LSM) which parameterizes turbulent e ow using main e ow characteristics such as mean e ow, velocity variance and Lagrangian time scale. In addition to numerical results, theoretical results based on the LSM are also considered, providing asymptotics of r, s and predictability time. It is shown that both numerical and theoretical LSM results for the center of mass error ( r) provide a good qualitative description, and a quantitatively satisfactory estimate of results from QG experiments. The scatter error ( s) results, on the other hand, are only qualitatively reproduced by the LSM.

Analysis of Flow Conditions in Freejet Experiments for Studying Airfoil Self-Noise

A new set of mean wall pressure data has been collected on a controlled diffusion airfoil at a chord Reynolds number of 1.2 £ £105 in a freejet anechoic wind tunnel. Comparisons of the experimental data with Reynoldsaveraged Navier‐ Stokes (RANS) simulationsin freeairshow signie cant e owe eld and pressure loading differences, indicatingsubstantialjetinterferenceeffects.Toanalyzetheseeffects,asystematicRANS-basedcomputationale uid dynamicsstudyoftheexperimentale owconditionshasbeencarriedout,whichquantie esthestrongine uenceofthe e nite jet (nozzle) width on the aerodynamic loading and e ow characteristics. When the jet width is not sufe ciently large compared to the frontal wetted area of the airfoil, the airfoil pressure distribution is found to be closer to the distribution on a cascade than that of an isolated proe le. The airfoil lift is signie cantly reduced. Accounting for the actual wind-tunnel setup recovers the wall pressure distribution on the airfoil without further empirical angle-of-attack corrections. These jet interference effects could be responsible for the discrepancies among some earlier experimental and computational studies of airfoil self-noise. They should be accounted for in future noise computations to ensure that the experimental e ow conditions are simulated accurately.

Analysis of Inducer Recirculating Inlet Flow

The mean and turbulent features of inducer inlet e ow covering various operating points of a centrifugal pump are analyzed. Measurements are conducted in an air test facility with a e ve-hole pressure probe and an X-wire probe. For e ow rates lower than the design e ow rate, the recirculation located upstream of the inducer is very strong and creates a global rotation of the e uid from the tip to the hub, upsteam of the inducer. The axial extent of the separated e ow decreases as the e ow rate increases. The stagnation pressure in this region is higher than the upstream stagnation pressure and can reach several times the inlet dynamic head. In the inlet channel axis, within the recirculated e ow, the stagnation pressure is lower than what is found for upstream stations outside the recirculation. This can be related to upstream e uid motion and mixing with the inverse e ow, providing stagnation pressure losses. For the e ow rates where the recirculation region is large, the incoming e ow is dee ected toward the hub. Phase-averaged measurements in the inducer inlet show the main time-dependant e ow features and their evolutionwiththee owrate.Theanalysisshowsthat,atdesign andhighere owrates,theevolution ofthemeridional velocity is correlated with the evolution of the relative e ow angle. Relative velocity is not affected by the blade leading edge and is constant at a given radius. The change in the axial velocity is mainly due to the sudden change of the relative e ow angle before the blade leading edge.

Relative dispersion at the surface of the Gulf of Mexico

We examine the relative motion of pairs and triplets of surface drifters in the Gulf of Mexico. The mean square pair separations grow exponentially in time from the smallest resolved scale (1 km) to 40‐ 50 km, with an e-folding time of 2‐ 3 days. Thereafter, the dispersion exhibits a power law dependence on time with an exponent of between 2 and 3 (depending on the measure used) up to scales of several hundred kilometers. The straining is for the most part isotropic, with only weak regional variations. But there are suggestions of anisotropy in the western basin, probably due to boundary current advection. The pair velocities are correlated during the early phase and a portion of the late phase. The relative displacement distributions during the early phase are, after an initial adjustment, nonGaussian and approximately constant, suggestive of local straining. The triplet results likewise suggest two growth phases. During the early phase, the mean area and the longest triangle leg grow exponentially in time, the latter with a rate consistent with the two-particle results. Most triangles are drawn out during this time. During the late period, the triangles grow and their aspect ratios systematically decrease, suggesting an evolution to an equilateral shape. Although surface divergences should affect these statistics, they nevertheless strongly resemble those found with two-dimensional turbulent e ows. If so, we would infer an enstrophy cascade at scales below the deformation radius (40‐ 50 km) which is probably spectrally local. The latter implies that growth in particle separations comes from e ow features the same size as the separations. It is also possible there is an inverse energy cascade to scales larger than the deformation radius, driven possibly by baroclinic instability. However, the late period statistics may also ree ect dispersion by a large scale shear.

Numerical Simulation of Aerodynamic Damping for Flutter Analysis of Turbomachinery Blade Rows

This paper describes the calculation of aerodynamic damping for prediction of e utter characteristics of turbomachinery bladerows.Theunsteady aerodynamicbladeloadsareobtainedbysolving theNavier ‐Stokesequations on a dynamically deforming, body-e tted grid. Phase-lagged boundary conditions are used to model the nonzero interbladephaseangleoscillations,and theenergy exchangemethod isused to calculatetheaerodynamicdamping. The analysis is applied to calculate e utter of a transonic forward-swept fan cone guration, which showed e utter at part speed conditions in wind-tunnel tests. The analysis successfully identie ed the most critical mode and the e ow characteristics responsible for the observed e utter. The location of shock wave and variation of its strength were found to strongly ine uence the aerodynamic damping, with outboard stations providing the main contribution. The results also demonstrate that changes in blade shape impact the calculated aerodynamic damping, indicating the importance of using an accurate blade operating shape under centrifugal and steady aerodynamic loading. Sensitivity of thecalculated aerodynamic damping to variation in inlet and exit conditions, the computational time steps, and blade natural frequency are also reported.

Assessment of Rotor Blade Angle of Attack from Experimental Inflow Data

A series of experiments was conducted by NASA Langley Research Center and the U.S. Army, over a 10-year period beginning in the mid-1980s, to provide some insight into the nature of helicopter rotor-system-induced velocity and to provide calibration data for many promising computational methods. Rotor-induced velocities were measured above the rotor system for several forward e ight-test conditions in the NASA Langley Research Center 14 by 22 Foot Subsonic Tunnel using a 15%-scale, fully articulated, stiff-in-torsion rotor and in a joint government/industry partnershipwith Bell HelicopterTextron,Inc.,foralarger,aeroelastically scaled, bearingless rotor. Atwo-componentlaservelocimeterwasused to makethesemeasurements in thefacility.Thedata fromthese tests have been published previously as NASA quick release reports and conference papers, and they are available electronically. Further analyses of the data to assess the local angle of attack of the rotor blades as a function of azimuth, span, and test condition aredocumented. The results indicatethat assessing ine owusing thetime average ofa rotorrevolutiondoesnotalwayscaptureadequately thelocaleffectsofbladepassageontheine owdistribution. The ine ow distribution should be assessed using the average of the blade azimuth-dependent ine ow. At advance ratioslessthan0.30, theeffectsof theindividual trailing vorticeswereevidentintheine owmeasurements, andthey have a signie cant impact on the local blade e ow angle. For higher advance ratios, the blade azimuth-dependent ine ow velocities differed very little from the time-averaged ine ow characteristics. The analyses demonstrated that dynamic twist is signie cant for aeroelastically scaled rotors and must be measured or modeled to assess the rotor performance accurately.