A note on the relaxation equations of the bulk viscosity of a liquid

It is found that the existing equations for the bulk viscosity coefficient of a liquid have to be suitably modified in order to suit the experimental data of ultrasonic absorption and dispersion. The modification is effected by introducing a dimensionless quantity, the values of which are evaluated for a few organic liquids by comparison with experimental data. Temperature variation of this parameter is also studied. Ultrasonic relaxation times are also evaluated and their variation with temperature is discussed. © 1973, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.