Model experiment and numerical simulation of marginal pressure in the flow field downstream of the stenostic vessel in vitro / 生物医学工程学杂志

For the defects of interpreting the relationship between the distribution and severity of vascular stenostic disease and the low shear stress, the study focus on and explore the rules of the pressure distribution and variation downstream of the stenostic vessel with the numerical simulation and the hydrodynamic model of turbulent flow separation area for in vitro experiment. The results reveal that there is a good compatibility between the model experiment and the numerical simulation; there exists a marked pressure decrease downstream of the stenosis. And the distribution area of low pressure is similar to the characteristic distribution of the stenostic vessel diseases. The study suggested that the numerical simulation can be applied in the study of micro-flow field; the presure distribution and variatioin downstream of the stenostic vessel maybe another factor to trigger the pathogenesis of vessel stenostic diseases.

A preliminary study on the extraction method of velocity pulsated signals in the velocity spectrum image of pulsed Doppler ultrasounds in vitro / 生物医学工程学杂志

Focus on the defects of the extraction method of velocity pulsated signals in the velocity spectrum image of pulsed Doppler ultrasounds (such as the limited data, great amount of work and low reproducibility), we combine the earlier research results and the basic rules of the velocity spectrum image, and employing the visual basics plateau, to design and develop a software to extract the velocity signals from the spectrum image automatically. Compare the mean velocity and RNS between the PIV and the PDU resulting from the method, the correlations are r = 0.93 and r = 0.78 respectively. The study reveals the software increase the amount of valid data, decrease the amount of work and increase reproducibility of the signals extraction. The method may be an effective way to analyse the velocity spectrum image of PDU in clinic.

Design and adjustment of a hydrodynamic model of turbulent flow separation area for in vitro experiment on the downstream of tubal stenosis / 生物医学工程学杂志

This paper reports the establishment of a model of turbulent flow separation area for experiment on the downstream of tubal stenosis, and adjust it to cooperate with the velocity and turbulent shear stress (TSS) detection by means of the particle image velocimetry (PIV), and with the pressure detection of pressure sensor in vitro. The velocity, TSS and wall pressure characteristics of the downstream of tubal stenosis were quantitatively detected and analyzed via the PIV and pressure sensor. And the hydrodynamic characteristics of the velocity, TSS and wall pressure in the flow separation area were primarily understood. The model can cooperate smoothly with the PIV and pressure sensor to detect the velocity, TSS and wall pressure; there exist low velocity, low TSS and low pressure in the flow separation area downstream of tubal stenosis.