Showing papers on "Freestream published in 1992"
01 Oct 1992
TL;DR: In this article, two new versions of the k-omega two-equation turbulence model are presented, the baseline model and the Shear-Stress Transport model, which is based on the BSL model, but has the additional ability to account for the transport of the principal shear stress in adverse pressure gradient boundary layers.
Abstract: Two new versions of the k-omega two-equation turbulence model will be presented. The new Baseline (BSL) model is designed to give results similar to those of the original k-omega model of Wilcox, but without its strong dependency on arbitrary freestream values. The BSL model is identical to the Wilcox model in the inner 50 percent of the boundary-layer but changes gradually to the high Reynolds number Jones-Launder k-epsilon model (in a k-omega formulation) towards the boundary-layer edge. The new model is also virtually identical to the Jones-Lauder model for free shear layers. The second version of the model is called Shear-Stress Transport (SST) model. It is based on the BSL model, but has the additional ability to account for the transport of the principal shear stress in adverse pressure gradient boundary-layers. The model is based on Bradshaw's assumption that the principal shear stress is proportional to the turbulent kinetic energy, which is introduced into the definition of the eddy-viscosity. Both models are tested for a large number of different flowfields. The results of the BSL model are similar to those of the original k-omega model, but without the undesirable freestream dependency. The predictions of the SST model are also independent of the freestream values and show excellent agreement with experimental data for adverse pressure gradient boundary-layer flows.
1,709 citations
TL;DR: The k-omega model for eddy-viscosity turbulence does not require damping functions in the viscous sublayer, and its equations are less stiff near the wall.
Abstract: The Wilcox (1988, 1991) k-omega model for eddy-viscosity turbulence does not require damping functions in the viscous sublayer, and its equations are less stiff near the wall. It has been designed to predict the requisite wake length in equilibrium, adverse pressure-gradient boundary-layer flows. When applied to free shear layers, however, a strong dependency of its results on the freestream value of omega has been noted. This feature is presently investigated via the self-similar equations for incompressible equilibrium boundary layers.
356 citations
01 Jan 1992
TL;DR: In this paper, a semi-infinite flat plate with an elliptic leading edge is simulated numerically and the incompressible flow past the flat plate is computed by solving the full Navier-Stokes equations in general curvilinear coordinates.
Abstract: The receptivity to freestream sound of the laminar boundary layer over a semi-infinite flat plate with an elliptic leading edge is simulated numerically. The incompressible flow past the flat plate is computed by solving the full Navier-Stokes equations in general curvilinear coordinates. A finite-difference method which is second-order accurate in space and time is used. Spatial and temporal developments of the the Tollmien-Schlichting wave in the boundary layer, due to small-amplitude time-harmonic oscillations of the freestream velocity that closely simulate a sound wave travelling parallel to the plate, are observed. The effect of leading-edge curvature is studied by varying the aspect ratio of the ellipse. Boundary layer over the flat plate with a sharper leading edge is found to be less receptive. The relative contribution of the discontinuity in curvature at the ellipse-flat-plate juncture to receptivity is investigated by smoothing the juncture with a polynomial. Continuous curvature leads to less receptivity. A new geometry of the leading edge, a modified super-ellipse, which provides continuous curvature at the juncture with the flat plate, is used to study the effect of continuous curvature and inherent pressure gradient on receptivity.
94 citations
TL;DR: In this article, the effects of fine scale turbulence were represented by a two-equation (k-e) closure model that included a generalized formulation, low Reynolds number terms, and a compressibility correction.
Abstract: Steady flowfields resulting from slot injection at the surface of a flat plate in a freestream with a Mach number of 3.7 and a unit Reynolds number of 5.83 x 10 6 /m were simulated numerically by integration of the time-dependent compressible mass-averaged Navier-Stokes equations. Effects of fine scale turbulence were represented by a two-equation (k-e) closure model that included a generalized formulation, low Reynolds number terms, and a compressibility correction
91 citations
TL;DR: In this article, single-shot and frame-averaged fluorescence images have been acquired for nonreacting and reacting flows in side-view and end-view orientations.
Abstract: Planar laser-induced fluorescence (PLIF) imaging has been used to examine the mixing and combustion of a sonic jet of gas injected transversely into a supersonic freestream flowing within a shock tube. Single-shot and frame-averaged fluorescence images have been acquired for nonreacting and reacting flows in side-view and end-view orientations. In the nonreacting experiments, nitric oxide seeded within the jet fluid was used to examine the penetration and mixing of the jet with the freestream, without the influence of chemical reaction and heat release. In the reacting experiments, the hydroxyl radical (OH), formed by the combustion of a hydrogen jet injected into an oxidizing freestream, was used to locate the reaction zones. The OH images indicate that combustion takes place primarily in the shear layer formed by the jet and the freestream, and in the boundary layer adjacent to the wall. For both the nonreacting and reacting results, the single-shot images show the presence of large-scale turbulent structures not apparent in the frame-averaged images. These results demonstrate the importance of examining and understanding the instantaneous flowfield, because it is the instantaneous, rather than mean state, of the flow that ultimately determines the extent to combustion.
90 citations
TL;DR: In this article, a mixing study using gas injection at low transverse angles into M = 3 and M = 6 crossflows was presented, and the effects of injectant asymmetries on the mixing processes were also tested by including low injector yaw angles.
Abstract: We present a mixing study using gas injection at low transverse angles into M=3 and M=6 crossflows. Effects of injectant asymmetries on the mixing processes were also tested by including low injector yaw angles. Ambient temperature helium was injected at matched pressure conditions as well as at 5× matched pressure into a Mach 6 freestream, with Reynolds number of 5.4×10 7 /m. Complementary tests at Mach 3, Re=5.0×10 7 /m, were performed. The primary data are concentration measurements and meanflow measurements with nanosecond exposure shadowgraphs and surface flow visualization
84 citations
TL;DR: In this article, a boundary-layer transition study on a sharp, 5° half-angle cone at various angles of attack was conducted at Mach 3.5, and the transition was found to be less receptive to freestream acoustic disturbances than first-mode (Tollmien-Schlichting) dominated transition.
Abstract: A boundary-layer transition study on a sharp, 5° half-angle cone at various angles of attack was conducted at Mach 3.5. Transition data were obtained with and without significantly reduced freestream acoustic disturbance levels. A progressive downstream and upstream motion of the transition front on the windward and leeward rays, respectively, of the cone with angle of attack was observed for the high noise level data in agreement with data trends obtained in conventional (“noisy”) wind tunnels. However, the downstream movement was not observed to the same degree for the low noise level data in the present study. Transition believed to be crossflow dominated was found to be less receptive to freestream acoustic disturbances than first-mode (Tollmien-Schlichting) dominated transition. The previously-developed crossflow transition Reynolds number criterion, χtr,max≈200, was found to be inadequate for the current case. An improved criterion is offered, which includes compressibility and flow-geometry effects.
80 citations
TL;DR: In this article, the problem of boundary layer heat transfer with very high freestream turbulence is investigated, and a new heat transfer parameter, St-prime, is proposed to characterize turbulent boundary layers heat transfer on the domain 0-0.65.
Abstract: Boundary layer heat transfer with very high freestream turbulence is investigated. The problem is studied experimentally by placing a constant-temperature heat transfer surface at various locations in the margin of a turbulent free jet and measuring both the surface heat transfer rate and the turbulence in the freestream. Freestream turbulent fluctuations 20 to 60 percent relative to the mean velocity augment heat transfer 1.8 to 4 times that which would be predicted locally using accepted correlations for turbulent boundary layers at the same Reynolds number. The correlations of Simonich and Bradshaw (1989), Pedisius et al. (1983), and Blair (1983) each fail to describe the present data. For flows over flat surfaces in air with very high freestream turbulence, greater than 0.2, u-prime determines h. A new heat transfer parameter, St-prime, characterizes turbulent boundary layer heat transfer with freestream turbulence on the domain 0-0.65 to within +/- 15 percent for high Reynolds number flows with uniform thermal boundary conditions.
78 citations
TL;DR: A review of existing experimental results for slender bodies and delta wings, tested at high angles of attack, reveals that no physical evidence exists that vortex asymmetry on slender pointed bodies or delta wings has ever occurred through the so-called hydrodynamic instability process as mentioned in this paper.
Abstract: A review of existing experimental results for slender bodies and delta wings, tested at high angles of attack, reveals that no physical evidence exists that vortex asymmetry on slender pointed bodies or delta wings has ever occurred through the so-called hydrodynamic instability process. It will be shown that in the numerous tests performed, asymmetric flow separation and/or asymmetric flow reattachment, were the flow mechanisms triggering the vortex asymmetry. Slender wing rock is found to result from a basic lack of roll damping, existing for attached leading-edge vortices, and the vortex-asymmetry is generated at nonzero roll angle, i.e., for asymmetric flow conditions. Nomenclature b = wingspan c = reference length, d CQ = delta wing center chord d = maximum diameter of body of revolution € = rolling moment, coefficient C€ = €/(p00U£/2) Re = Reynolds number based on d and freestream conditions S — reference area, ird2/4 or projected wing area U = horizontal velocity Y = side force, coefficient CY = Y/(pJJl/2) a = angle of attack OA = aPex half-angle Oc = cone half-angle A = leading-edge sweep p = air density = body roll angle Subscripts A = apex c = cone oo = freestream conditions
73 citations
01 Jul 1992
TL;DR: In this paper, the relative importance of axial vorticity sources in mixing the injectant with the freestream was investigated in a simulation of two generic wall fuel injectors.
Abstract: A class of contoured wall fuel injectors was designed to
enable shock-enhancement of hypervelocity mixing for
supersonic combustion ramjet applications. Previous
studies of these geometries left unresolved questions
concerning the relative importance of various axial vorticity
sources in mixing the injectant with the freestream. The
present study is a numerical simulation of two generic fuel
injectors which is aimed at elucidating the relative roles of
axial vorticity sources including: baroclinic torque through
shock-impingement, cross-stream shear, turning of
boundary layer vorticity, shock curvature, and diffusive flux.
Both the magnitude of the circulation, and the location of
vorticity with respect to the mixing interface were
considered. Baroclinic torque and cross-stream shear were
found to be most important in convectively mixing the
injectant with the freestream, with the former providing for
deposition of vorticity directly on the fue1/air interface.
60 citations
TL;DR: In this paper, a detailed formula is developed that can be used in both finite-volume (FV) and finite-difference (FD) methods for constructing freestream capturing metrics in space and time.
Abstract: A detailed formula is developed that can be used in both finite-volume (FV) and finite-difference (FD) methods for constructing freestream capturing metrics in space and time. It is shown that, considering an FV cell on the FD grid, the freestream capturing metrics in space and time can be constructed from the FD formulation. The approach is costly but guarantees the global conservation for an arbitrary motion of the grid.
TL;DR: In this article, hot-wire anemometry was employed to examine the laminar-to-turbulent transition of low-speed, two-dimensional boundary layers for two (moderate) levels of flow acceleration and various levels of grid-generated freestream turbulence.
Abstract: Hot-wire anemometry was employed to examine the laminar-to-turbulent transition of low-speed, two-dimensional boundary layers for two (moderate) levels of flow acceleration and various levels of grid-generated freestream turbulence. Flows with an adiabatic wall and with uniform-flux heal transfer were explored. All of the experimental test cases resulted in bypass-mode transitions, a conclusion based upon the observance of spots upstream of the theorelical minimum critical Reynolds number (three cases) or, for one case, upon the evidence that T-S mode amplification played no apparent role in the transition
TL;DR: In this article, the aerodynamic pressure distribution on hemispherical domes, in boundary layer flows, including the determination of the mean, standard deviation, minimum and maximum and area average pressure coefficients, was studied.
TL;DR: In this paper, the possible existence of a "law-of-the-wall" similarity velocity profile for 3D boundary layers was investigated using nine different proposed relations with the data from nine experiments carried out in 3D turbulent boundary layers.
Abstract: The possible existence of a "law-of-the-wall" similarity velocity profile for 3-D boundary layers was investigated using nine different proposed relations with the data from nine experiments carried out in 3-D turbulent boundary layers. Both for pressure driven and shear-driven flows, the "law-of-the-wall" relation of Johnston for the local freestream velocity direction component best applies. Although not well described by any relation, the crosswise velocity component of pressure-driven flows and shear-driven flows is best represented by Mager's relation and Chandrashekhar and Swamy equation, respectively.
01 Jun 1992
TL;DR: In this article, a full-scale F/A-18 was tested in the National Full-Scale Aerodynamic Complex at NASA Ames Research Center at Moffett Field, California, at an angle of attack range of 18 to 50 degrees and at wind speeds of up to 100 knots.
Abstract: This paper presents an overview of high angle-of-attack tests of a full-scale F/A-18 in the 80- by 120-Foot Wind Tunnel of the National Full-Scale Aerodynamic Complex at NASA Ames Research Center at Moffett Field, California. A production aircraft was tested over an angle-of-attack range of 18 to 50 deg and at wind speeds of up to 100 knots. These tests had three primary test objectives. Pneumatic and mechanical forebody flow control devices were tested at full-scale and shown to produce significant yawing moments for lateral control of the aircraft at high angles of attack. Mass flow requirements for the pneumatic system were found to scale with freestream density and speed rather than freestream dynamic pressure. Detailed measurements of the pressures buffeting the vertical tail were made and spatial variations in the buffeting frequency were found. The LEX fence was found to have a significant effect on the frequency distribution on the outboard surface of the vertical fin. In addition to the above measurements, an extensive set of data was acquired for the validation of computational fluid dynamics codes and for comparison with flight test and small-scale wind tunnel test results.
TL;DR: In this article, a model for axisymmetric shear layers is proposed, which assumes that the mixing process is dominated by large-scale coherent structures, locally described locally as linear instability waves.
Abstract: Models are described for the turbulent mixing of compressible, axisymmetric shear layers. The models assume that the mixing process is dominated by large-scale coherent structures. These large-scale structures are described locally as linear instability waves. Calculations are made for the development of the axisymmetric shear layer as a function of freestream Mach numbers and velocity and density ratios. The predictions for the axisymmetric shear layer are compared with both experimental measurements and predictions for a plane shear layer
01 Jun 1992
TL;DR: In this paper, the authors present a transonic, annular facility developed at the von Karman Institute to investigate the aerodynamic heat transfer performances of real size advanced aero-engine and gas turbine components at correctly simulated operating conditions.
Abstract: The purpose of this paper is to present the new transonic, annular facility developed at the von Karman Institute to investigate the aerodynamic heat transfer performances of real size advanced aero-engine and gas turbine components at correctly simulated operating conditions.The facility operates under the principle of an Isentropic Light Piston Compression Tube. Its definite advantage over classical blowdown wind tunnels is to independently model the freestream Mach and Reynolds numbers as well as the gas/wall/coolant temperature ratios. Its running time ranges between 0.1 and 1 s.The first part of the paper describes the design, the manufacturing and the installation of the different components of the wind tunnel and the test section. The second part deals with the different measurement techniques applied for aerodynamic and heat transfer measurements; it also describes some examples of the flow quality obtained in this new facility.Copyright © 1992 by ASME
TL;DR: In this article, a numerical study using the direct simulation Monte Carlo (DSMC) method is presented for hypersonic rarefied flow about a 1.6m-diameter sphere.
Abstract: Results of a numerical study using the direct simulation Monte Carlo (DSMC) method are presented for hypersonic rarefied flow about a 1.6-m-diameter sphere. The flow conditions considered are those experienced by a typical satellite in orbit or by a space vehicle during entry. The altitude range considered is that from 90 to 200 km, which encompasses the near continuum, transitional and free-molecular flow regimes. A freestream velocity of 7.5 km/s is assumed in the simulations. The results show that transitional effects are significant at all altitudes below 200 km, but at 200 km the flow about the sphere attains the free-molecular limit. Very little chemical activity is present above 120 km. Both the stagnation point heat transfer and the sphere drag approach their respective free molecule values at 200 km. Results highlight the thermal and chemical nonequilibrium nature of the flowfield. Nonequilibrium effects on the surface heating and body drag are also investigated.
TL;DR: In this paper, the effects of mass removal on the boundary layer of a normal shock with a turbulent boundary layer over a flat surface were investigated with and without imposing mass removal, showing that mass removal distorted the original shock pattern and eliminated the separation at the shock foot while reducing the boundary-layer thicknesses and growth rates.
Abstract: Interactions of a normal shock with a turbulent boundary layer over a flat surface were investigated with and without imposing mass removal. The approach flow was very nearly two-dimensional, with a uniform freestream Mach number of 1.48, strong enough to cause separation at the shock foot. Suction was imposed immediately upstream of the shock over a finely perforated surface, removing much of the boundary-layer flow. The time-mean wall pressure distributions and two components of the time-mean velocity vector field were determined for both cases. Mass removal distorted the original shock pattern and eliminated the separation at the shock foot while reducing the boundary-layer thicknesses and growth rates to less than half. Mass removal also introduced some undesirable effects: asymmetric sidewall boundary-layer growth in the subsonic flow and increased shock oscillation amplitudes. The removed mass flow varied strongly in the streamwise direction in a manner that indicated wide variations of the flow coefficients for the individual perforations.
TL;DR: A functional relationship was determined between nondimensional breathing zone concentration and contaminant source momentum and this relationship is supported by numerical simulations.
Abstract: Several factors affecting breathing zone concentration were examined in a paint spray booth by using a tracer gas method. The variables in the study include contaminant momentum, the presence of a flat plate downstream of the worker, the distance between the contaminant source and the body, and the worker's motion. A dramatic reduction in breathing zone concentration was observed when the spray gun emitted contaminants with high momentum. Reductions of 30-50% were observed because of the other variables. The source momentum effect was studied, subsequently, in a wind tunnel by measuring the breathing zone concentration of a mannequin with various flows through jets of different diameter, at varying freestream velocities. A functional relationship was determined between nondimensional breathing zone concentration and contaminant source momentum. This relationship is supported by numerical simulations. The effect of contaminant momentum on the near-wake flow field is discussed in conjunction with results fr...
01 Jul 1992
TL;DR: The ASU Transition Research Facility is commonly called the ASU Unsteady Wind Tunnel because of its unsteady-flow capability as mentioned in this paper, which is a closed return tunnel within which oscillatory flows of air can be generated for the study of low-speed aerodynamics.
Abstract: The ASU Transition Research Facility is commonly called the ASU Unsteady Wind Tunnel because of its unsteady-flow capability. This facility has been in operation since 1988. It is a closed return tunnel within which oscillatory flows of air can be generated for the study of unsteady problems in low-speed aerodynamics. Because it also has excellent low-turbulence characteristics, it has been used principally as a boundary-layer transition research facility. The wind tunnel is described along with its unsteady calibration data. Examples of freestream turbulence and boundary-layer transition measurements are given.
TL;DR: In this article, hot-wire anemometry was employed to examine the laminar-to-turbulent transition of low-speed, two-dimensional boundary layers for two (moderate) levels of flow acceleration and various levels of grid-generated freestream turbulence.
Abstract: Hot-wire anemometry was employed to examine the laminar-to-turbulent transition of low-speed, two-dimensional boundary layers for two (moderate) levels of flow acceleration and various levels of grid-generated freestream turbulence. Flows with an adiabatic wall and with uniform-flux heat transfer were explored. Conditional discrimination techniques were employed to examine the zones of flow within the transitional region
01 Jan 1992
TL;DR: In this article, the performance of a particular class of fuel injectors for Scramjet engine applications is addressed, and the effects of incoming boundary layer height and injector spacing, and injectant to free stream pressure and velocity ratios are investigated.
Abstract: The performance of a particular class of fuel injectors for
scramjet engine applications is addressed. The contoured
wall injectors were aimed at augmenting mixing through
axial vorticity production arising from interaction of the
fueVair interface with an oblique shock. Helium was used to
simulate hydrogen fuel and was injected at Mach 1.7 into a
Mach 6 airstream. The effects of incoming boundary layer
height. injector spacing, and injectant to freestream pressure and velocity ratios were investigated. Results from threedimensional flow field surveys and Navier-Stokes
simulations are presented. Performance was judged in
terms of mixing, loss generation and jet penetration.
Injector performance was strongly dependent on the
displacement effect of the hypersonic boundary layer which
acted to modify the effective wall geometry. The impact of
the boundary layer varied with injector array spacing.
Widely-spaced arrays were more resilient to the detrimental
effects of large boundary layers. Strong dependence on
injectant to free stream pressure ratio was also displayed.
Pressure ratios near unity were most conducive to losseffective mixing and strong jet penetration. Effects due to variation in mean shear associated with non-unity velocity ratios were found to be secondary within the small range of values tested.
TL;DR: In this article, a wind tunnel with very low stream disturbance levels comparable to free-flight conditions was used to predict the transition of the nozzle wall boundary layers of a supersonic flight vehicle.
Abstract: To advance boundary-layer stability and transition research and to ultimately provide reliable predictions of transition for supersonic flight vehicles, a wind tunnel is required with very low stream disturbance levels comparable to free-flight conditions. Previous investigations indicated that the freestream noise in pilot quiet nozzles is primarily caused by transition in the nozzle wall boundary layers that are subjected to Gortler instability
TL;DR: In this paper, two compressibility corrections to the standard k-e turbulence model are used with the Navier-Stokes equations to compute the mixing region between two streams of the same gas flowing under a variety of low and high-speed freestream conditions.
Abstract: Two compressibility corrections to the standard k-e turbulence model are used with the Navier-Stokes equations to compute the mixing region between two streams of the same gas flowing under a variety of low- and high-speed freestream conditions. The model corrections are assessed by comparing 1) computed spread rates for a series of unconfined flows with data for a range of convective Mach numbers, and 2) velocity profiles for a confined flow
TL;DR: In this paper, the interaction between a uniform flow and a two-dimensional counter flowing wall jet was investigated for various ratios of the jet velocity to the freestream velocity. But the results were limited to the wall penetration zone.
Abstract: Experimental results related to the interaction between a uniform flow and a two-dimensional counter flowing wall jet are presented for various ratios of the jet velocity to the freestream velocity. Both visual observations and wall pressure surveys were made in the jet penetration zone. Attempts were made to choose the proper scaling variables to suitably nondimensionalize the wall pressure distributions. The geometrical characteristics of the dividing streamline were determined for a range of test conditions
TL;DR: In this paper, a hot-wire anemometry measurement in an incompressible turbulent boundary-layer flow over a heated flat plate at zero pressure gradient was made using an x probe and a temperature fluctuation probe.
Abstract: Hot-wire anemometry measurements in an incompressible turbulent boundary-layer flow over a heated flat plate at zero pressure gradient were made using an x probe and a temperature fluctuation probe. The measurements were made for three different temperature difference cases between the wall and the freestream 10, 15, and 20 o C. Simultaneous measurements of the two components of the velocity and the temperature were made at the same point using an x probe and a temperature fluctuation probe
TL;DR: In this article, the effects of embedded, longitudinal vortices on heat transfer and film injectant downstream of two staggered rows of film cooling holes with compound angle orientations are described.
Abstract: Experimental results are presented that describe the effects of embedded, longitudinal vortices on heat transfer and film injectant downstream of two staggered rows of film cooling holes with compound angle orientations. Holes are oriented so that their angles with respect to the test surface are 30 deg in a spanwise/normal plane projection, and 35 deg in a streamwise/normal plane projection. A blowing ratio of 0.5, nondimensional injection temperature parameter θ of about 1.5, and freestream velocity of 10 m/s are employed. Injection hole diameter is 0.945 cm to give a ratio of vortex core diameter to hole diameter of 1.6-1.67 just downstream of the injection holes (x/d = 10.2). At the same location, vortex circulation magnitudes range from O.15 m 2 /s to O.18 m 2 /s
TL;DR: In this paper, the characteristics of stretched vortices in the stagnation region, due to the presence of freestream turbulence in the incident stream, were studied by means of spatial correlation.
Abstract: Characteristics of stretched vortices in the stagnation region, due to the presence of freestream turbulence in the incident stream, were studied by means of spatial correlation. The spanwise length scale of the stretched vortices, lm, and the characteristic height corresponding to the distance between the averaged position of the centres of the stretched vortices and the plate, Hv, are successfully correlated with the integral length scale of freestream turbulence.
01 Jun 1992
TL;DR: In this paper, measurements of the unsteady vortex flow over a wing-body at high angles of attack were carried out on a generic test model of a pointed body of revolution with double-delta wings.
Abstract: Measurements of the unsteady vortex flow over a wing-body at high angles of attack were carried out on a generic test model of a pointed body of revolution with double-delta wings. Vortex patterns and trajectories were quantified from digitized laser sheet video images. The velocity-field measurements showed the jetlike flow in the unburst vortex, unsteady secondary structures below the primary core, and then the reversed flow in the burst vortex. Results of hot-film anemometry revealed the presence of peak frequencies in the velocity spectra over the wing and near the trailing edge, which varied linearly with freestream speed and increased as the measurement point moved upstream. Good Strouhal correlation was found with previous results obtained for a smaller generic wing-body model.