DEFINITION OF TURBULENCE IN IN-CYLINDER FLOW-FIELDS

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.