Direct numerical simulation (DNS) is used to systematically investigate the applicability of minimal channel approach for the characterization of double-averaged velocity and temperature profiles in irregular rough surfaces. Roughness is generated mathematically using a random algorithm, in which the power spectrum (PS) and probability density function (PDF) of the surface height function can be prescribed. 12 different combinations of PS and PDF are examined at $Re_\tau$=500.

These files contain the data used in the publication:

“Study of irregular roughness in minimal channels” J. Yang, A. Stroh, S. Jakirlic, B. Frohnapfel and P. Forooghi published in proceeding ETMM13 doi: 10.5445/IR/1000140429

Numerical Details:

The carried out DNS is based on a pseudo-spectral solver for incompressible boundary layer flows developed at KTH/Stockholm. The Navier-Stokes equations are numerically integrated using the velocity-vorticity formulation by a spectral method with Fourier decomposition in the horizontal directions and Chebyshev discretization in the wall-normal direction. For temporal advancement, the convection and viscous terms are discretized using the 3rd order Runge-Kutta and Crank-Nicolson methods, respectively. The simulation domain represents an turbulent channel flow with periodic boundary conditions applied in streamwise and spanwise directions, while the wall-normal extension of the domain is bounded by no-slip and zero-temperature boundary conditions at the upper and lower domain wall. The flow is driven by a prescribed constant pressure gradient (CPG), a heat source term is added to the flow. The friction Reynolds number for the present case is fixed to Re_τ = 500. The structured surface is introduced through an immersed boundary method (IBM) based on the method proposed by Goldstein et al. (1993) and is essentially a proportional controller which imposes zero velocity in the solid region of the numerical domain.

Data Files:

The data files are saved and labeled in *.mat files. Each file contains MATLAB data consisting of the roughness height distribution and corresponding coordinates. The roughness structures are non-dimensionalized with the channel half height δ. The naming convention of the data in this database follows the JFM publication "DNS-based characterization of pseudo-random roughness in minimal channels" DOI: 10.1017/jfm.2022.33.

Reference:

Please provide a reference to the article above when using this data. Please direct questions regarding numerical setup/data to Jiasheng Yang (jiasheng.yang@kit.edu)