ИСТИНА

An experimental study of the stability of the blood vessel model conveying fluid has been conducted for turbulent flows and only few for laminar flows by various researchers in the context of biological applications. Although, under normal conditions, turbulence is present only a small portion of the cardiovascular system, whereas most of the blood flows are laminar. Thus, the flow regime influence on the collapsible tube oscillations is of great interest. The experimental study was conducted for identify the regimes of self-exciting oscillations of the elastic Penrose tubes conveying fluid on the Starling resistor. The model of a blood vessel (Penrose tube) stretched between two rigid tubes of the same diameter was studied. Water or various water solutions of glycerin are used as a working fluid. The effect of the turbulent and laminar regimes with equal flow rate and pressure drop were investigated and compared. Four types of oscillation for laminar and turbulent flow were observed by pressure drop, output pressure, microphone measurements and visualization of the tube collapse mode. It was found that stability loss in the turbulent flow regime happens at a lower pressure drop than in the laminar flow. Further, a comparison of the transitions between the types of oscillations was conducted depending on the pressure drop for laminar and turbulent flows. The reported study was funded by RFBR, project number 20-31-90018 and 18-29-10020. The reported study was funded by RFBR, project number 20-31-90018 and 18-29-10020.