INVESTIGATION OF THE PRESSURE DISTRIBUTION IN A FLOW OF A VISCOUS FLUID IN A PIPELINE UNDER HYDRAULIC-SHOCK CONDITIONS WITH ACCOUNT FOR THE RELAXATION PROPERTIES OF THE FLUID

An exact analytical solution of the hyperbolic equation defining the pressure distribution in a viscous fluid flowing in a pipeline under the conditions of a hydraulic shock with account for the relaxation properties of the fluid has been obtained. It was established, based on acomparison of calculation and experimentaldata, that the relaxation properties of such a fluid determine the degree of nonstationarity of its flow and, hence, the wall friction of the fluid or its shear stress. It is shown that, in the case of nonstationary movement of a viscous fluid in a pipeline under hydraulic-shock conditions, the pressure jump caused by the hydraulic shock differs markedly in form (it is longer in time) from that in the case of quasi-stationary movement of this fluid under the identical conditions. The same effect (although weaker) was detected for decrease in the indicated pressure jump.