We carry out direct numerical simulation of experimental grid turbulence, for which the mesh Reynolds number is 2500. The grid is directly constructed in the computational domain. The streamwise computational domain size is >100 times the mesh size. The value of the decay exponent n is estimated as n ≈ 1.36 by using a ratio defined by the turbulent kinetic energy and its dissipation. The prevailing perspective is that the memory of the turbulence cannot be considered as short. In this paper, we propose a promoter that focuses on the generation of turbulence using the grid, not on the shape of the grid, as addressed in previous studies (Hurst & Vassilicos (2007); Krogstad & Davidson (2011)), from a multiscale perspective and investigate the effects of the turbulence-generating method on the decay exponent n. Specifically, n is increased to n ≈ 1.53 and 1.41 because of the changes in the initial conditions.