Showing papers on "Freestream published in 2013"

Apparent Transition Behavior of Widely-Used Turbulence Models

Abstract: The Spalart-Allmaras and the Menter SST k-omega turbulence models are shown to have the undesirable characteristic that, for fully turbulent computations, a transition region can occur whose extent varies with grid density. Extremely fine two-dimensional grids over the front portion of an airfoil are used to demonstrate the effect. As the grid density is increased, the laminar region near the nose becomes larger. In the Spalart-Allmaras model this behavior is due to convergence to a laminar-behavior fixed point that occurs in practice when freestream turbulence is below some threshold. It is the result of a feature purposefully added to the original model in conjunction with a special trip function. This degenerate fixed point can also cause non-uniqueness regarding where transition initiates on a given grid. Consistent fully turbulent results can easily be achieved by either using a higher freestream turbulence level or by making a simple change to one of the model constants. Two-equation k-omega models, including the SST model, exhibit strong sensitivity to numerical resolution near the area where turbulence initiates. Thus, inconsistent apparent transition behavior with grid refinement in this case does not appear to stem from the presence of a degenerate fixed point. Rather, it is a fundamental property of the k-omega model itself, and is not easily remedied.

Influence of ZNMF jet flow control on the spatio-temporal flow structure over a NACA-0015 airfoil

Abstract: The spatio-temporal flow structure associated with zero-net-mass-flux (ZNMF) jet forcing at the leading edge of a NACA-0015 airfoil (Re = 3 × 104) is investigated using high-repetition rate particle image velocimetry. Measurements are performed at an angle of attack of 18°, where in the absence of forcing, flow separation occurs at the leading edge. Forcing is applied at a frequency of f + = 1.3 and a momentum coefficient c μ = 0.0014 for which previous force measurements indicated a 45 % increase in lift over the unforced case. The structure and dynamics associated with both the forced and unforced case are considered. The dominant frequencies associated with separation in the unforced case are identified with the first harmonic of the bluff body shedding f wake closely corresponding to the forcing frequency of f + = 1.3. A triple-decomposition of the velocity field is performed to identify the spatio-temporal perturbations produced by the ZNMF jet forcing. This forcing results in a reattachment of the flow, which is caused by the generation of large-scale vortices that entrain high-momentum fluid from the freestream. Forcing at 2f wake produces a series of vortices that advect parallel to the airfoil surface at a speed lower than the freestream velocity. Potential mechanisms by which these vortices affect flow reattachment are discussed.

Stabilization of a hypersonic boundary layer using a wavy surface

Abstract: Stability of a supersonic near-wall flow over a shallow grooved plate in the freestream of Mach 6 is investigated by means of numerical simulations and wind-tunnel experiments. Numerical solutions of two-dimensional Navier–Stokes equations are used to model propagation of artificial disturbances of several fixed frequencies generated by an actuator placed on the wall. It is shown that the high-frequency forcing excites unstable waves in the flat-plate boundary layer. These waves are relevant to the second-mode instability. The wavy wall damps the disturbances in a high-frequency band while it enhances them at lower frequencies. Stability experiments are conducted in the Institute of Theoretical and Applied Mechanics Tranzit-M shock tunnel under natural freestream conditions. The measured disturbance spectra are similar to those predicted numerically. They contain a peak associated with the second-mode instability. This peak is damped by the wavy wall, while a marginal increase of the disturbance amplitude...

Simulations of mixing in an inlet-fueled axisymmetric scramjet

Abstract: An unsteady simulation of a simple axisymmetric inlet-fueled scramjet engine concept is performed using a hybrid Reynolds-averaged Navier–Stokes and large-eddy simulation approach. The freestream has a Mach number of 7.5 with Mach 8 flight enthalpy. The simulation is of a nonreacting case in which hydrogen is injected into nitrogen. The simulation is used to provide a detailed description of the structure of the flow. The simulation shows that a large-scale pair of counter-rotating vortices forms within the scramjet combustor, with rotation opposite to the rotation of the pair that forms further upstream due to the interaction of the fuel plume with the crossflow. This vortex pair is found to significantly alter the shape of the hydrogen fuel plume and increase the rate at which the hydrogen is mixing by more than a factor of 2 compared to before the vortex pair is formed. The distribution of hydrogen is examined in detail. The time-averaged and fluctuating wall pressures, the mean velocity field, and res...

Experimental investigation on transverse jet penetration into a supersonic turbulent crossflow

Abstract: The paper evaluates the evolvement of coherent structures and penetration height of gaseous transverse jet penetration into a supersonic turbulent flow. The high spatiotemporal resolution coherent structures of the jet plume are obtained by utilizing the nanoparticle-based planar laser scattering technique (NPLS). The evolving pattern of the coherent structures generated on the upwind surface of the transverse jet is analyzed based on the NPLS images. The shedding eddies from the jet near-field have lower convection velocity along freestream direction, while vortex growth rate is apparently higher than the far-field. Farther downstream, the large-scale eddies have less deformation and translate at velocities near the freestream velocity. Thus the near-field determines the scale of eddies in the far-field and affects the whole mixing process. The effect of injection stagnation pressure on the coherent structures is discussed and a modified penetration correlation is proposed based on an edge approximation definition and least square method with various injection pressures.

Film Cooling in Laminar and Turbulent Supersonic Flows

Abstract: Film-cooling experiments of generic supersonic flat-plate flows have been conducted at the Shock Wave Laboratory, RWTH Aachen University, for the laminar and turbulent boundary-layer regimes. To obtain a cooling film, coolant is injected through different blowing geometries to the surface of the plate. The model geometry as well as the width of the blowing slots have been carefully chosen to guarantee a two-dimensional flow at the centerline. Therefore, all blowing geometries share the same width. Different injection angles and coolant mass flow rates, as well as different freestream conditions, are investigated to obtain an empirical correlation for the cooling efficiency, a value often referred to in literature that describes the cooling effect.

Influence of common modeling choices for high-speed transverse jet-interaction simulations

Abstract: Numerical simulations were carried out to determine the sensitivity of results to a variety of geometric and flow parameters commonly employed in high-speed transverse jet-interaction calculations. The configuration consisted of a single circular, flush-wall porthole injector inclined at 30 deg to the freestream in a Mach 4.0 crossflow. Injection was sonic with a jet-to-freestream momentum flux ratio of 2.1. The primary modeling parameters investigated include turbulence model, freestream turbulence intensity, turbulent Schmidt number, and several injector-pipe configurations. The simulations were conducted using the multispecies Reynolds-averaged Navier–Stokes equations with a number of popular turbulence models including the one-equation Spalart–Allmaras model and the two-equation Menter shear stress transport, two-equation realizable k-e, and two-equation nonlinear (cubic) k-e models. The results were found to be very sensitive to both the choice of turbulence model and value of the turbulent Schmidt n...

Laser ignition of hypersonic air–hydrogen flow

Abstract: An experimental investigation of the behaviour of laser-induced ignition in a hypersonic air–hydrogen flow is presented. A compression-ramp model with port-hole injection, fuelled with hydrogen gas, is used in the study. The experiments were conducted in the T-ADFA shock tunnel using a flow condition with a specific total enthalpy of 2.5 MJ/kg and a freestream velocity of 2 km/s. This study is the first comprehensive laser spark study in a hypersonic flow and demonstrates that laser-induced ignition at the fuel-injection site can be effective in terms of hydroxyl production. A semi-empirical method to estimate the conditions in the laser-heated gas kernel is presented in the paper. This method uses blast-wave theory together with an expansion-wave model to estimate the laser-heated gas conditions. The spatially averaged conditions found with this approach are matched to enthalpy curves generated using a standard chemical equilibrium code (NASA CEA). This allows us to account for differences that are introduced due to the idealised description of the blast wave, the isentropic expansion wave as well as thermochemical effects.

Separation Control on a Low-Pressure Turbine Blade using Microjets

Abstract: Flow separation that occurs over low-pressure turbine blades at low Reynolds numbers has been a cause of concern due to its detrimental effect on engine performance. In the present study, the effect of microjet actuation, a low-mass, high-momentum device, is demonstrated for the elimination of separation on a low-pressure turbine blade over a wide range of Reynolds numbers using a range of complementary diagnostics, which include the surface pressure, velocity field, and wake-loss measurements. The U.S. Air Force Research Laboratory L1A low-pressure turbine blade used in this study is a highly aftloaded profile that experiences a nonreattaching separation at approximately 60% axial chord at low Reynolds numbers. Baseline blade pressure distributions as well as wake-loss coefficient measurements show that the blade experiences nonreattaching separation for Reynolds numbers based on axial chord less than 50,000 for a freestream turbulence intensity of 1% with steady inlet conditions. Microjet-based control ...

Density Measurements of a Turbulent Wake Using Acetone Planar Laser-Induced Fluorescence

Abstract: The application of a planar density measurement technique for compressible flowfields based on acetone planar laser-induced fluorescence is presented. An error analysis indicates a minimum inherent uncertainty of ∼2.5% in density measurements due to uncertainty in local pressure and a total experimental uncertainty of 8%, primarily driven by shot noise due to low-signal levels. The technique is demonstrated through the visualization of the separated shear layer and turbulent wake of a wall-mounted hemisphere at a freestream Mach number of 0.78 and a Reynolds number of approximately 900,000. The flow is marked by a large-scale flapping motion of the wake and low-density vortex cores, where density drops of up to 50% of the freestream density are detected. In addition, closeup images of the shear layer near the separation point reveal the formation of lambda shocks. The density fields are used to perform aerooptic distortion calculations through spatial integration of the density field. A correlation is fou...

Flows around a cascade of flat plates with acoustic resonance

Abstract: In order to better understand the effects of acoustic resonance on flows around a cascade of flat plates, fluid structures and acoustic fields were examined by aeroacoustic direct simulations and wind tunnel experiments. Computations and experiments were performed for the flows around five parallel plates with and without the acoustic resonance changing the freestream velocity. The aspect ratio of the plates, C/b, is 15.0, and the separation-to-thickness ratio, s/b, is 6.0. For the resonant condition of a freestream velocity of 44 m/s, the Reynolds number based on the plate thickness, b, and the freestream velocity is 5.8 × 103. The computational results revealed that large-scale vortices composed of fine-scale vortices are shed in the wake of the plates. Both experimental and computational results indicated that the shedding of the large-scale vortices is more synchronized in the spanwise direction for the resonant condition. Moreover, the shedding of the large-scale vortices from one plate and those from the neighboring plates become more synchronized in the resonant condition. The mode of this synchronization was found to be an anti-phase mode, in which the vortex is shed from the upper or lower face of one plate when the vortex is shed from the lower or upper faces of the neighboring plates. Computation of the flow around a single plate was also performed, and the radiation of the acoustic waves from the downstream edge due to vortex shedding from the plate was indicated. When acoustic resonance occurs in the flows around the cascade of flat plates, vortex shedding in the above-mentioned mode contributes to the intensification of the standing waves between the plates. Moreover, standing waves were demonstrated to induce new vortices around the upstream edges of the plates in synchronization.

Scaling Laws in Canopy Flows: A Wind-Tunnel Analysis

Abstract: An analysis of velocity statistics and spectra measured above a wind-tunnel forest model is reported. Several measurement stations downstream of the forest edge have been investigated and it is observed that, while the mean velocity profile adjusts quickly to the new canopy boundary condition, the turbulence lags behind and shows a continuous penetration towards the free stream along the canopy model. The statistical profiles illustrate this growth and do not collapse when plotted as a function of the vertical coordinate. However, when the statistics are plotted as function of the local mean velocity (normalized with a characteristic velocity scale), they do collapse, independently of the streamwise position and freestream velocity. A new scaling for the spectra of all three velocity components is proposed based on the velocity variance and integral time scale. This normalization improves the collapse of the spectra compared to existing scalings adopted in atmospheric measurements, and allows the determination of a universal function that provides the velocity spectrum. Furthermore, a comparison of the proposed scaling laws for two different canopy densities is shown, demonstrating that the vertical velocity variance is the most sensible statistical quantity to the characteristics of the canopy roughness.

Numerical Study of Pressure Fluctuations due to a Mach 6 Turbulent Boundary Layer

Abstract: Direct numerical simulations (DNS) are used to examine the pressure fluctuations generated by a Mach 6 turbulent boundary layer with nominal freestream Mach number of 6 and Reynolds number of Re(sub t) approx. =. 464. The emphasis is on comparing the primarily vortical pressure signal at the wall with the acoustic freestream signal under higher Mach number conditions. Moreover, the Mach-number dependence of pressure signals is demonstrated by comparing the current results with those of a supersonic boundary layer at Mach 2.5 and Re(sub t) approx. = 510. It is found that the freestream pressure intensity exhibits a strong Mach number dependence, irrespective of whether it is normalized by the mean wall shear stress or by the mean pressure, with the normalized fluctuation amplitude being significantly larger for the Mach 6 case. Spectral analysis shows that both the wall and freestream pressure fluctuations of the Mach 6 boundary layer have enhanced energy content at high frequencies, with the peak of the premultiplied frequency spectrum of freestream pressure fluctuations being at a frequency of omega(delta)/U(sub infinity) approx. = 3.1, which is more than twice the corresponding frequency in the Mach 2.5 case. The space-time correlations indicate that the pressure-carrying eddies for the higher Mach number case are of smaller size, less elongated in the spanwise direction, and convect with higher convection speeds relative to the Mach 2.5 case. The demonstrated Mach-number dependence of the pressure field, including radiation intensity, directionality, and convection speed, is consistent with the trend exhibited in experimental data and can be qualitatively explained by the notion of "eddy Mach wave" radiation.

Investigations on the Turbulent Wake of a Generic Space Launcher Geometry in the Hypersonic Flow Regime

Abstract: The turbulent wake flow of generic rocket configurations is investigated experimentally and numerically at a freestream Mach number of 6.0 and a unit Reynolds number of 10 · 10 6 .T heflow condition is based on the trajectory of Ariane V at an altitude of 50km, which is used as baseline to address the overarchingtasks of wakeflows in the hypersonicregimelikefluid-structuralcoupling,reversehot jets and base heating. Experiments using pressure transducers and high-speed schlieren measurement technique were conducted to gain insight into the local pressure fluctuations on the base and the oscillations of the recompression shock. This experimental configuration features a wedge-profiled strut orthogonally mounted to the main body. Additionally, the influence of cylindrical nozzle extensions attached to the base of the rocket is investigated, which is the link to the numerical investigations. Here, the axisymmetric model possesses a cylindrical sting support of the same diameter as the nozzle extensions. The sting supportallows investigationsof a undisturbedwakeflow. A time-accurate zonal RANS/LES approachwas applied to identify shocks, expansion waves, and the highly unsteady recompression region numerically. Subsequently,experimentaland numericalresults in the strut-avertedregionare opposed with regardto the wall pressure and recompression shock frequency spectra. For the compared configurations, experimental pressure spectra exhibit dominant Strouhal numbers at about SrD = 0.03 and 0.27 and the recompression shock oscillates at 0.2. In general, the numerical pressure and recompression shock fluctuations agree satisfactorily to the experimental results. The experiments with a blunt base reveal base-pressure spectra with dominant Strouhal numbers at 0.08 at the center position and 0.145, 0.21 − 0.22 and 0.31 − 0.33 at the outskirts of the base.

Computational Fluid Dynamics Investigation of Human Aspiration in Low-Velocity Air: Orientation Effects on Mouth-Breathing Simulations

Abstract: Computational fluid dynamics was used to investigate particle aspiration efficiency in low-moving air typical of occupational settings (0.1-0.4 m s(-1)). Fluid flow surrounding an inhaling humanoid form and particle trajectories traveling into the mouth were simulated for seven discrete orientations relative to the oncoming wind (0°, 15°, 30°, 60°, 90°, 135° and 180°). Three continuous inhalation velocities (1.81, 4.33, and 12.11 m s(-1)), representing the mean inhalation velocity associated with sinusoidal at-rest, moderate, and heavy breathing (7.5, 20.8, and 50.3 l min(-1), respectively) were simulated. These simulations identified a decrease in aspiration efficiency below the inhalable particulate mass (IPM) criterion of 0.5 for large particles, with no aspiration of particles 100 µm and larger for at-rest breathing and no aspiration of particles 116 µm for moderate breathing, over all freestream velocities and orientations relative to the wind. For particles smaller than 100 µm, orientation-averaged aspiration efficiency exceeded the IPM criterion, with increased aspiration efficiency as freestream velocity decreased. Variability in aspiration efficiencies between velocities was low for small (<22 µm) particles, but increased with increasing particle size over the range of conditions studied. Orientation-averaged simulation estimates of aspiration efficiency agree with the linear form of the proposed linear low-velocity inhalable convention through 100 µm, based on laboratory studies using human mannequins.

The effect of freestream turbulence on fixed and flapping micro air vehicle wings

Abstract: This thesis details an experimental investigation into the effects of elevated levels of large-scale freestream turbulence on the aerodynamics of a micro air vehicle wing in fixed, flapping, and pitching configurations Such large-scale turbulence is typi

Two-Dimensional Shock-Wave/Boundary-Layer Interaction in the Presence of Entropy Layer

Abstract: Results of experimental and numerical study of gas flow and heat transfer in the region of interference of the impinging oblique shock wave with the near-wall flow on sharp and blunt plates are presented. The study is performed for the freestream Mach numbers from 5 to 10 and Reynolds numbers from 0.3×106 to 27×106 corresponding to the laminar and turbulent undisturbed boundary layers. The plate bluntness, location of the impinging shock, and the shock strength are varied. It is shown that the plate bluntness significantly reduces the heat transfer in the interference region due to the increase of separation-zone size and the reduction of gas density in the high-entropy layer. As the plate bluntness increases the heat transfer decays to a certain threshold value of the bluntness radius. The bluntness effect on the heat transfer increases and the bluntness threshold value decreases with the freestream Mach number.

Synthetic Jets as a Boundary Vorticity Flux Control Tool

Abstract: Nomenclature A = synthetic jet amplitude, m∕s a = acceleration c = chord length d = slot width f = body force f = jet actuation frequency, Hz f = nondimensional actuation frequency, fxTE∕U∞ H = cavity height h = slot height n = unit normal vector pointing out of the flow P = pressure S = distance along surface th = thickness t = time U∞ = freestream velocity VJ = mean jet expulsion velocity W = cavity width xTE = distance from synthetic jet to trailing-edge μ = dynamic viscosity ρ = density σ = boundary vorticity flux, m∕s ω = vorticity ω = angular frequency, 2πf

Flat plate film cooling from a single-row inclined holes embedded in a trench: effect of external turbulence and flow acceleration

Abstract: Results of an experimental study of a flat plate film cooling efficiency from a single row of inclined holes embedded in a “shallow” trench are presented. It is shown the cooling efficiency of such a configuration is much greater than that of the traditional configuration of inclined round holes. This provides more uniform surface coverage by the coolant film. The flow external turbulence increases the film cooling efficiency by 5–8%, while the freestream flow acceleration reduces it by 10–15%.

Revised Parametric Ideal Scramjet Cycle Analysis

Abstract: Nomenclature A ∕A = area ratio, Eq. (17) A2 = diffuser (engine inlet) exit area, cm ; combustor entrance area ao = freestream speed of sound, m∕s cp = specific heat at constant pressure, kJ∕ kg · K F = thrust, N F∕ _ mo = specific thrust, N∕ kg∕s f = fuel-to-air ratio gc = Newton’s constant, kg · m ∕ N · s hPR = fuel lower heating value, kJ∕kg Mc = combustion Mach number Mo = Mach number at freestream flight conditions M o = freestream Mach number for maximum F∕ _ mo M o = freestream Mach number for minimum S M o = freestream Mach number for maximum F∕A2 M9 = Mach number at engine nozzle exit (M9 0 M9 0 0 M9 Mo), Eq. (3) Po = freestream static pressure, Pa R = gas constant for air, kJ∕ kg · K S = thrust-specific fuel consumption, mg∕ N · s T = temperature, K Tmax = material temperature limit, K T 0 max = burner exit total temperature, Eq. (7a),Mc < Mo, K T 0 0 max = burner exit total temperature, Eq. (7b), Mc ≥ Mo, K To = freestream ambient temperature, K Tto = freestream total temperature (Tt2 Tto), K T9 = temperature at engine nozzle exit, K (also T9 0 and T9 0 0 ) V9 = engine nozzle exit velocity, m∕s (also V9 0 and V9 0 0 ) γ = ratio of specific heats ηT = thermal efficiency ηP = propulsive efficiency ηo = overall efficiency τr = inlet temperature ratio, Tto∕To 1 γ − 1 Mo∕2 τλ = total temperature to freestream temperature ratio, Eq. (6) τb = τb τλ∕τr

The effect of flow speed and body size on Kármán gait kinematics in rainbow trout

Abstract: We have little understanding of how fish hold station in unsteady flows. Here, we investigated the effect of flow speed and body size on the kinematics of rainbow trout Karman gaiting behind a 5 cm diameter cylinder. We established a set of criteria revealing that not all fish positioned in a vortex street are Karman gaiting. By far the highest probability of Karman gaiting occurred at intermediate flow speeds between 30 and 70 cm s(-1). We show that trout Karman gait in a region of the cylinder wake where the velocity deficit is about 40% of the nominal flow. We observed that the relationships between certain kinematic and flow variables are largely preserved across flow speeds. Tail-beat frequency matched the measured vortex shedding frequency, which increased linearly with flow speed. Body wave speed was about 25% faster than the nominal flow velocity. At speeds where fish have a high probability of Karman gaiting, body wavelength was about 25% longer than the cylinder wake wavelength. Likewise, the lateral (i.e. cross-stream) amplitude of the tail tip was about 50% greater than the expected lateral spacing of the cylinder vortices, while the body center amplitude was about 70% less. Lateral body center acceleration increased quadratically with speed. Head angle decreased with flow speed. While these values are different from those found in fish swimming in uniform flow, the strategy for locomotion is the same; fish adjust to increasing flow by increasing their tail-beat frequency. Body size also played a role in Karman gaiting kinematics. Tail-beat amplitudes of Karman gaiting increased with body size, as in freestream swimming, but were almost three times larger in magnitude. Larger fish had a shorter body wavelength and slower body wave speed than smaller fish, which is a surprising result compared with freestream swimming, where body wavelength and wave speed increased with size. In contrast to freestream swimming, tail-beat frequency for Karman gaiting fish did not depend on body size and was a function of the vortex shedding frequency.

An Exploration of Radial Flow on a Rotating Blade in Retreating Blade Stall

Abstract: The nature of radial flow during retreating blade stall on a two-bladed teetering rotor with cyclic pitch variation is investigated using laser sheet visualization and particle image velocimetry in a low-speed wind tunnel. The velocity field above the retreating blade at 270◦ azimuth shows the expected development of a radially directed jet layer close to the blade surface in the otherwise separated flow region. This jet is observed to break up into discrete structures, limiting the spanwise growth of the radial velocity in the jet layer. The discrete structures are shown to derive their vorticity from the “radial jet” layer near the surface, rather than from the freestream at the edge of the separated region. The separation line determined using velocity data shows the expected spanwise variation. The results of this study are also correlated in a limited range of extrapolation to the phenomena encountered on a full-scale horizontal axis wind turbine in yaw.

Experimental Study of Boundary-Layer Response to Laser-Generated Disturbances at Mach 6

Abstract: Surface-mounted pressure sensors were used to investigate the response of a hypersonic conical boundary layer to artificial disturbances. A pulsed high-power laser was focused to a spot about 5 mm above the model. When a certain intensity threshold is exceeded, the air is no longer transparent, the laser energy is absorbed, and a plasma ignites. This plasma very quickly reassociates and an expanding shock wave and a volume of heated gas in the disturbance center remain. Because this center was some distance above the model, only the shock wave interacted with the boundary layer and, as a result of this interaction, a second-mode-like wave train evolved. The wave’s behavior is compared with uncontrolled natural waves, which originated from freestream disturbances. The measurements yield the spatial extensions, the frequency content, and the wave structure. Furthermore, the effects of changing the Reynolds number and applying multipulses to affect the frequency content were investigated.

The Freestream Turbulence Effect in Solar-Wind/Magnetosphere Coupling: Analysis Through the Solar Cycle and for Various Types of Solar Wind

Abstract: The freestream turbulence effect is a viscous interaction between the solar wind and the Earth's magnetosphere wherein the driving of the magnetosphere is stronger when the amplitude of the solar-wind turbulence upstream of the Earth is stronger. The origin of the effect is an eddy viscosity of the solar wind controlled by the amplitude of the ambient MHD turbulence. The present study investigates outstanding issues about the operation of the turbulence effect. For this study, a large solar-wind/magnetosphere data set is assembled: to the 1963-2001 OMNI2 data set, 1-hour-lagged values of the auroral-electrojet index are added. The 1963-2001 OMNI2-AE 1 data set has ∼193,000 hours of data that can be used to study magnetospheric driving by the turbulence effect. The freestream turbulence effect is analyzed for southward IMF by holding -vB z fixed in the data set. Under modest southward IMF, the turbulence effect has the same strength as it does under northward IMF. For large -vB z where reconnection driving is strong the ability to measure the freestream turbulence effect deteriorates owing to signal-to-noise issues. The freestream turbulence effect was analyzed for 3 solar cycles of data: a weak solar-cycle dependence to the strength of the turbulence effect was found. A categorization of the solar wind was developed from the temperature-versus-speed plot for the solar wind. Using these categorizations, plus data with restrictions on the sunspot number, plus catalogs of solar-wind events, no differences in the freestream turbulence effect were seen between different types of solar wind hitting the magnetosphere.