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FIG. 11. Mean velocity field and isocounters of the streamwise velocity in the (y,z) planes in the wake of the Ahmed body at Re=768 000: [(a), (c), and (e)] Experimental measurements of Lienhart er al. (Ref. 3) and [(b), (d), and (f)] present LES results measured at locations x/h=—0.132 [(a) and (b)], x/h =0.278 [(c) and (d)], and x/h=1.74 [(e) and (f)].

Figure 11 Mean velocity field and isocounters of the streamwise velocity in the (y,z) planes in the wake of the Ahmed body at Re=768 000: [(a), (c), and (e)] Experimental measurements of Lienhart er al. (Ref. 3) and [(b), (d), and (f)] present LES results measured at locations x/h=—0.132 [(a) and (b)], x/h =0.278 [(c) and (d)], and x/h=1.74 [(e) and (f)].

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FIG. 1. Sketch with dimensions of the Ahmed body.
FIG. 1. Sketch with dimensions of the Ahmed body.
FIG. 2. Visualization of the mesh in the entire channel (a) and around the bluff body (b) in the median vertical plane. B. Time scheme
FIG. 2. Visualization of the mesh in the entire channel (a) and around the bluff body (b) in the median vertical plane. B. Time scheme
TABLE I. Distances of the first grid palits to the car wall: y;,, at the roof, Voor at the bottom, x7,,,, at the front, and x*,,, at the rear of the "body.
TABLE I. Distances of the first grid palits to the car wall: y;,, at the roof, Voor at the bottom, x7,,,, at the front, and x*,,, at the rear of the "body.
FIG. 3. Turbulent kinetic energy profiles in spanwise direction at three different abscissa.
FIG. 3. Turbulent kinetic energy profiles in spanwise direction at three different abscissa.
FIG. 4. Spectral kernel of the 1D SVV operator for different values of the threshold frequency my, N={40, 190, 170}.
FIG. 4. Spectral kernel of the 1D SVV operator for different values of the threshold frequency my, N={40, 190, 170}.
TABLE II. Characteristic length scales evaluated for the Ahmed body flow at Re=768 000.
TABLE II. Characteristic length scales evaluated for the Ahmed body flow at Re=768 000.
FIG. 5. Resolution on the roof (a) and downstream at the ground (b): y* in the streamwise direction and in the symmetry plane. Here dgyy corresponds to dy and U=(u). Contributions of the different terms of simplified equations of boundary layer (14) and (15).
FIG. 5. Resolution on the roof (a) and downstream at the ground (b): y* in the streamwise direction and in the symmetry plane. Here dgyy corresponds to dy and U=(u). Contributions of the different terms of simplified equations of boundary layer (14) and (15).
FIG. 8. 2D streamlines computed from the mean 2D velocity field ((u), (v)) in the plane z=0 and locations of the temporal measurement points.
FIG. 8. 2D streamlines computed from the mean 2D velocity field ((u), (v)) in the plane z=0 and locations of the temporal measurement points.
FIG. 7. Power spectral density of the time variations of u at different points over the bluff body; see points A, B, C and D of Fig. 8
FIG. 7. Power spectral density of the time variations of u at different points over the bluff body; see points A, B, C and D of Fig. 8
FIG. 9. (Color) Visualization of the vortical structures in the wake of the Ahmed body (Re=768 000): (a) Mean three-dimensional streamlines in the wake colored by the mean streamwise velocity (u); (b) isocontour of the turbulent kinetic energy k on the slant; (c) isosurfaces (p)=0.25 and (p)=—0.07 of the mear pressure, colored by the dimensionless turbulent kinetic energy k and showing the velocity field on the slant and in the wake; and (d) isosurface of the pressure fluctuations colored by the mean streamwise velocity (uw) on the slant and in the wake. Contours of structures reminiscent of horseshoe vortices are blackened
FIG. 9. (Color) Visualization of the vortical structures in the wake of the Ahmed body (Re=768 000): (a) Mean three-dimensional streamlines in the wake colored by the mean streamwise velocity (u); (b) isocontour of the turbulent kinetic energy k on the slant; (c) isosurfaces (p)=0.25 and (p)=—0.07 of the mear pressure, colored by the dimensionless turbulent kinetic energy k and showing the velocity field on the slant and in the wake; and (d) isosurface of the pressure fluctuations colored by the mean streamwise velocity (uw) on the slant and in the wake. Contours of structures reminiscent of horseshoe vortices are blackened
FIG. 10. Mean velocity field in the symmetry plane z=0 in the near wake of the Ahmed body, Re=768 000: (a) Experimental measurements of Lienhart et al. (Ref. 3) and (b) present LES results.
FIG. 10. Mean velocity field in the symmetry plane z=0 in the near wake of the Ahmed body, Re=768 000: (a) Experimental measurements of Lienhart et al. (Ref. 3) and (b) present LES results.
FIG. 12. Turbulence statistics in the symmetry plane z=0 over the slant and in the near wake of the Ahmed body at Re=768 000: [(a) and (b)] Profiles of the mean streamwise velocity, [(c) and (d)] profiles of the mean vertical velocity, and (e) profile of the turbulent kinetic energy. Comparisons of the numerical results, with and without near wall treatment, to the experimental results of Lienhart et al. (Ref. 3).
FIG. 12. Turbulence statistics in the symmetry plane z=0 over the slant and in the near wake of the Ahmed body at Re=768 000: [(a) and (b)] Profiles of the mean streamwise velocity, [(c) and (d)] profiles of the mean vertical velocity, and (e) profile of the turbulent kinetic energy. Comparisons of the numerical results, with and without near wall treatment, to the experimental results of Lienhart et al. (Ref. 3).
FIG. 13. Power spectral density of the fluctuations of the density uw at three locations in the wake. (a) (x=0.27, y=0.44), (b) (x=3.1, y=0.44), and (c) (x=6.83, y=0.44). Comparisons with Kolmogorov theory (K41 curve). The SVV threshold my, defines the range of frequencies in which the SVV acts.
FIG. 13. Power spectral density of the fluctuations of the density uw at three locations in the wake. (a) (x=0.27, y=0.44), (b) (x=3.1, y=0.44), and (c) (x=6.83, y=0.44). Comparisons with Kolmogorov theory (K41 curve). The SVV threshold my, defines the range of frequencies in which the SVV acts.
FIG. 14. Sketch of anisotropic tensor b,; in the Lumley triangle (Ref. 35) in the wake of the Ahmed body at Re=768 000: vs the y-axis at left, (a) (x =0.27, z=0), (c) (x=3.1, z=0), and (e) Gx 6.83, z=0) and vs the z-axis at right, (b) (v=0.27, y=0.44), (d) (v=3.1, y=0.44), and (f) (v=6.83, y=0.44).
FIG. 14. Sketch of anisotropic tensor b,; in the Lumley triangle (Ref. 35) in the wake of the Ahmed body at Re=768 000: vs the y-axis at left, (a) (x =0.27, z=0), (c) (x=3.1, z=0), and (e) Gx 6.83, z=0) and vs the z-axis at right, (b) (v=0.27, y=0.44), (d) (v=3.1, y=0.44), and (f) (v=6.83, y=0.44).
FIG. 15. Dissipation rate of the turbulent kinetic energy times Re at three different abscissa in the wake: (a) vs the vertical direction, z=0; (b) vs the spanwise direction, y=0.674.
FIG. 15. Dissipation rate of the turbulent kinetic energy times Re at three different abscissa in the wake: (a) vs the vertical direction, z=0; (b) vs the spanwise direction, y=0.674.
Related topics:
EngineeringLarge Eddy SimulationInvariant TheoryShear FlowComputational Method
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