# Effect of Surface Roughness on Aerodynamic Loads of Bluff Body in Vicinity of Smoothed Moving Wall
## 1 Introduction
Simulations [11; 27; 37] were conducted for a fixed Reynolds number of \(\mathrm{Re}=1\times 10^{5}\), in which the full cessation of the vortex shedding was successively captured. In other words, the Strouhal number completely disappeared, and the drag force was substantially reduced under surface roughness effects. Recently, [PERSON] and [PERSON] [15] proposed a new technique to change the cutoff width of the vorticity characteristic distribution as a function of the Reynolds number, because until then, there was a significant overestimation of the drag coefficient [40] of the single circular cylinder for Reynolds numbers from the upper range of the subcritical regime [1]. This did not allow the capture of the drag crisis when applying the DVM. Greater difficulties have been observed for simulations in the critical and supercritical regimes, highlighting the high sensitivity of the flow to small fluctuations in turbulence [15; 38; 40]. Thus, the Lagrangian Dynamic Roughness Model (MLDRVL) with Large Eddy Simulation (LES) was extensively tested by [PERSON] and [PERSON] [15], and the results compared with the experimental results of [PERSON] [29], [PERSON] [41], and [PERSON] [42], mainly to predict the drag crisis in rough circular cylinders in the Reynolds number range \(2\times 10^{4}\leq\mathrm{Re}\leq 6\times 10^{5}\). The MLDRVL was proposed to impose refined boundary layer conditions with the simultaneous contribution of rough geometry constructed with uniform triangular elements and a small-scale momentum injection near the wall. With regard to recent advances in CFD for flow studies on bluff bodies, work by [PERSON] et al. [43] can be distinguished by the use of the transverse traveling wave wall control method used to inhibit vortex shedding from a fixed circular cylinder. [PERSON] et al. [44] used the spacing ratio to analyze the flow after three cylinders in an equilateral triangular arrangement. In the same direction, cylinder arrangement techniques have been combined with boundary layer control to influence the subsequent wake. For example, there is the side-by-side arrangement of rotating cylinders [45] and the tandem arrangement of rough cylinders [46]. In another direction, [PERSON] and [PERSON] [47] adopted LESs to deal with the oscillating boundary in investigating the transient flow around an oscillating cylinder. In addition to the study of bluff bodies, the DVM, aided with LES, has supported investigations into the behavior of aircraft vortex wakes under the influence of crosswinds in landing and take-off operations, without considering [48] or considering [49] the roughness of the airport runway. The conditions of the influence of heat transfer through mixed convection on the rebound of vortical structures when encountering a heated runway [50] were analyzed with the DVM without LESs. In this context, [PERSON] et al. [49] used the roughness model of [PERSON] et al. [27]. The roughness model chosen in this work (MLDRVL) differs from the model by [PERSON] et al. [27] in the momentum injection strategy near the wall and addition of the construction of a rough geometry to the circular cylinder. Although both are Lagrangian approaches and use LES theory. [PERSON] et al. [49] also presented a recent review concerning the need to reduce the computational time of vortex methods; the new algorithms have been associated with multipole expansions, parallel implementation with Compute Unified Device Architecture--CUDA--technologies, and the construction of a neural network description of Lagrangian vortices. The purpose of this study was to adapt the model of [PERSON] [PERSON] [15] to demonstrate a turbulence control technique for a Large Eddy Simulation combined with the Discrete Vortex Method. The new technique was then applied to capture the vortex shedding suppression from a surface cylinder with different roughness heights, namely \(0.00110\leq\epsilon/\mathrm{D}\leq 0.02\).