TY - JOUR
T1 - Impact of Blood Rheology on Transition to Turbulence and Wall Vibration Downstream of a Stenosis
AU - Costa, Rayanne Pinto
AU - Nwotchouang, Blaise Simplice Talla
AU - Yao, Junyao
AU - Biswas, Dipankar
AU - Casey, David
AU - McKenzie, Ruel
AU - Sebastian, Frederick
AU - Amini, Rouzbeh
AU - Steinman, David A.
AU - Loth, Francis
N1 - Funding Information:
The authors acknowledge the support of Dale Ertley for manufacturing the stenosis model used in this study and the University of Akron.
Publisher Copyright:
© 2023 American Society of Mechanical Engineers (ASME). All rights reserved.
PY - 2023/1/1
Y1 - 2023/1/1
N2 - Previous experimental flow studies have demonstrated a delay (~20%) in transition to turbulence for whole blood compared to a Newtonian analog fluid in both a straight pipe and eccentric stenosis model with ridged walls. The impact of wall compliance on the transition to turbulence of blood compared to Newtonian analog and on wall vibration is unknown. The present study employed flexible walls downstream of an eccentric stenosis model and examined the wall vibration during the transition to turbulence with whole blood and a Newtonian analog. Measurements of tube wall vibration velocity (WVV) were used as an indicator of the turbulence level within the flexible tube. WVV was measured at 5, 10, and 15 diameters downstream of the stenosis using a laser Doppler vibrometer at Reynolds numbers 0, 200, 300, 350, 400, 450, 500, 550, 600, 650, 700, and 750. The root mean squares (RMS) of the measured WVV were utilized as an indirect measure of fluid velocity fluctuations present at that location, and hence, an indicator of transition to turbulence. WVV RMS was near-constant until approximately Reynolds number 400. It increased monotonically with Reynolds number for both whole blood and the Newtonian fluid. No differences in the transition to turbulence were observed between whole blood and the Newtonian fluid, as the WVV RMS curves were remarkably similar in shape. This result suggests that rheology had minimal impact on the WVV downstream of a stenosis for transition to turbulence since the fluids had a similar level of vibration.
AB - Previous experimental flow studies have demonstrated a delay (~20%) in transition to turbulence for whole blood compared to a Newtonian analog fluid in both a straight pipe and eccentric stenosis model with ridged walls. The impact of wall compliance on the transition to turbulence of blood compared to Newtonian analog and on wall vibration is unknown. The present study employed flexible walls downstream of an eccentric stenosis model and examined the wall vibration during the transition to turbulence with whole blood and a Newtonian analog. Measurements of tube wall vibration velocity (WVV) were used as an indicator of the turbulence level within the flexible tube. WVV was measured at 5, 10, and 15 diameters downstream of the stenosis using a laser Doppler vibrometer at Reynolds numbers 0, 200, 300, 350, 400, 450, 500, 550, 600, 650, 700, and 750. The root mean squares (RMS) of the measured WVV were utilized as an indirect measure of fluid velocity fluctuations present at that location, and hence, an indicator of transition to turbulence. WVV RMS was near-constant until approximately Reynolds number 400. It increased monotonically with Reynolds number for both whole blood and the Newtonian fluid. No differences in the transition to turbulence were observed between whole blood and the Newtonian fluid, as the WVV RMS curves were remarkably similar in shape. This result suggests that rheology had minimal impact on the WVV downstream of a stenosis for transition to turbulence since the fluids had a similar level of vibration.
KW - blood
KW - fluid dynamics
KW - laser Doppler vibrometer
KW - non-Newtonian
KW - rheology
KW - transition
KW - turbulence
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U2 - 10.1115/1.4055856
DO - 10.1115/1.4055856
M3 - Article
C2 - 36193889
AN - SCOPUS:85143551950
SN - 0148-0731
VL - 145
JO - Journal of Biomechanical Engineering
JF - Journal of Biomechanical Engineering
IS - 4
M1 - 041001
ER -