Langley Research Center Turbulence Modeling Resource

LES: Compressible Axisymmetric Transonic Separated Bump

Return to: Data from LES - Intro Page

The data on this page were provided by A. Uzun of NIA.

This compressible LES case is for axisymmetric separating flow over the Bachalo-Johnson transonic bump (AIAA Journal, Vol. 24, No. 3, 1986, pp. 437-443). Some experimental data are available at the: ATB: Axisymmetric Transonic Bump page. The LES was run using a compressible code. The publication is:

• Uzun, A. and Malik, M. R., "Wall-Resolved Large-Eddy Simulations of Transonic Shock-Induced Flow Separation," AIAA Paper 2018-3854, January 2018, https://doi.org/10.2514/6.2018-3854.
• Uzun, A. and Malik, M. R., "Wall-Resolved Large-Eddy Simulations of Transonic Shock-Induced Flow Separation," AIAA Journal, Vol. 57, No. 5, 2019, pp. 1955-1972, https://doi.org/10.2514/1.J057850.

This is a wall-resolved compressible-flow LES computation at M=0.875. Several different variants were run for the study, but only one result (with the highest resolution used) is available here. This is believed to be the most accurate computed result. Some relevant information is given below, but the interested reader is referred to the paper for more details:

• M=0.875
• Reynolds number (based on U_in and c) = 2,763,000, where U_in is the freestream velocity and c is the hump chord.
• To reduce the grid requirements, an overset grid was used whose overlap region occurred within the boundary layer.
• Re_theta is approximately 6600 (1.5c upstream of the leading edge)
• The domain "span" is 120 degrees
• Farfield grid extent is r/c=10
• Total grid size is 24 billion grid points

Long-time averaged LES data are provided below. The geometry is described in detail in the paper. To summarize, the cylinder diameter was 15.24 cm. The bump chord was 20.32 cm, with thickness of 1.905 cm and arc radius 0.5(t² + 0.25c²)/t. There was a small leading edge fillet with radius 18.30 cm.

The following figure shows the configuration:

The field data below contains LES time-averaged results with lengthscale nondimensionalized by chord. The data include mean flow variables density, u-velocity, v-velocity, and pressure; and turbulence quantities uu, vv, ww, and uv. Note the data is divided into 2 zones, inner (11841 x 351) and outer (5921 x 139).

Nondimensional mean flow and turbulence mean field data is provided here (note that these are gzipped Tecplot formatted files, so you must either have Tecplot or know how to read their format in order to use it. See README.tecplot):

• TransonicBump-Statistics-InnerGrid.dat.gz (219.5 Mb)
• TransonicBump-Statistics-OuterGrid.dat.gz (43.4 Mb)

Nondimensional velocity derivatives are provided here (note that these are gzipped Tecplot formatted files, so you must either have Tecplot or know how to read their format in order to use it. See README.velderivs.tecplot):

• TransonicBump-VelocityDerivatives-InnerGrid.dat.gz (134.4 Mb)
• TransonicBump-VelocityDerivatives-OuterGrid.dat.gz (26.8 Mb)

Surface pressure coefficients:

• TransonicBump-Cp.dat

Surface skin friction coefficients:

• TransonicBump-Cf.dat

Return to: Data from LES - Intro Page

Privacy Act Statement

Accessibility Statement

Responsible NASA Official: Ethan Vogel
Page Curator: Clark Pederson
Last Updated: 11/05/2021