Definition of Turbulence in In-Cylinder Flow Fields

抄録

The definition of turbulence of in-cylinder flow fields has been an important issue for researchers working on in-cylinder gas motion. This study proposes a definition of the "turbulence component" in both the calculation and measurement. Also, a new method to make a precise comparison between the calculation and measurement is presented theoretically. This method implies changing the coefficient, C_D, which is included in expressions for turbulence energy, its dissipation rate and turbulence length scale. Employing this method demonstrates the possibility of reducing the ambiguity of the cut-off frequency method to determine turbulence experimentally and also of improving the reliability of the calculation code.