Maximum grid spacing effect on peak pressure computation using inflow turbulence generators

• Published in: Results in engineering Vol. 15; p. 100491
• Main Authors: Mansouri, Zahra, Selvam, Rathinam Panneer, Chowdhury, Arindam Gan
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-09-2022; Elsevier
• Subjects: Computational fluid dynamics; Large eddy simulation; Peak pressure; Synthetic inflow turbulence; TTU building; TTU building; Peak pressure; Synthetic inflow turbulence; Large eddy simulation; Computational fluid dynamics
• ISSN: 2590-1230; 2590-1230
• DOI: 10.1016/j.rineng.2022.100491

The peak pressures are computed using computational fluid dynamics (CFD) with the synthetic inflow turbulence generator and compared with 1:6 scale Texas Tech University (TTU) wind tunnel measurements. The inflow turbulence is calculated using the Consistent Discrete Random Flow Generation Method (CDRFG) method. The maximum and minimum frequencies from the field or experimental measurements as input to the inflow turbulence generator without considering the largest grid spacing used in the CFD model leads to high pressure error. For one case, more than 100% error in peak pressure results is observed. In addition, spurious pressures are observed at the building location without building. By varying maximum frequencies systematically for each computational mesh size and comparing the velocities and pressures at the inflow and the building location without building, possible causes of the error are explained. From the investigation, it is suggested not to use the maximum frequency in the inflow turbulence generator beyond the frequency that can be transported by the largest grid spacing.
•The largest grid spacing h in the domain determines the highest velocity fluctuations' frequency transported by the grid.•The suggested highest frequency using the FDM is fLES = fgrid = H/4 h, where 4 h is the smallest wavelength resolved by the grid.•If fmax used as input to the inflow turbulence models is greater than fLES, spurious pressures produced in the domain.•Spurious pressures lead to high errors in computing peak pressure on the building.