### Abstract

Available in vitro and in vivo experimental observations suggest that red cell aggregation and blood vessel geometry are important determinants of the flow characteristics of blood in venules. However, no consistent relationship has been observed between red blood cell aggregation and vascular resistance. The present work attempts to understand this relationship by evaluating computationally the effect of red cell aggregation on the flow characteristics of blood in a converging vessel bifurcation. The proposed mathematical model considers blood as a two-phase continuum, with a central core region of concentrated red cell suspension that is surrounded by a layer of plasma adjacent to the vessel wall. In the central core region, blood is described by Quemada's non-Newtonian rheological model, in which local viscosity is a function of both the local hematocrit and a structural parameter that is related to the size of red blood cell aggregates. Fluids from the two feeding branches are immiscible, which results in a stratified multiphase flow in the collecting venule. Calculations predict a complex, three-dimensional pattern of blood flow and generally nonaxisymmetric distribution of velocity, hematocrit, and shear stress in the collecting venule. The calculations are a first step toward a realistic model of blood flow in the venous microcirculation.

Original language | English (US) |
---|---|

Pages (from-to) | 135-153 |

Number of pages | 19 |

Journal | Annals of Biomedical Engineering |

Volume | 25 |

Issue number | 1 |

State | Published - Jan 1997 |

### Fingerprint

### Keywords

- Hemorheology
- Mathematical model
- Quemada model
- Venous microcirculation

### ASJC Scopus subject areas

- Biomedical Engineering

### Cite this

*Annals of Biomedical Engineering*,

*25*(1), 135-153.

**Stratified multiphase model for blood flow in a venular bifurcation.** / Das, B.; Enden, G.; Popel, Aleksander S.

Research output: Contribution to journal › Article

*Annals of Biomedical Engineering*, vol. 25, no. 1, pp. 135-153.

}

TY - JOUR

T1 - Stratified multiphase model for blood flow in a venular bifurcation

AU - Das, B.

AU - Enden, G.

AU - Popel, Aleksander S

PY - 1997/1

Y1 - 1997/1

N2 - Available in vitro and in vivo experimental observations suggest that red cell aggregation and blood vessel geometry are important determinants of the flow characteristics of blood in venules. However, no consistent relationship has been observed between red blood cell aggregation and vascular resistance. The present work attempts to understand this relationship by evaluating computationally the effect of red cell aggregation on the flow characteristics of blood in a converging vessel bifurcation. The proposed mathematical model considers blood as a two-phase continuum, with a central core region of concentrated red cell suspension that is surrounded by a layer of plasma adjacent to the vessel wall. In the central core region, blood is described by Quemada's non-Newtonian rheological model, in which local viscosity is a function of both the local hematocrit and a structural parameter that is related to the size of red blood cell aggregates. Fluids from the two feeding branches are immiscible, which results in a stratified multiphase flow in the collecting venule. Calculations predict a complex, three-dimensional pattern of blood flow and generally nonaxisymmetric distribution of velocity, hematocrit, and shear stress in the collecting venule. The calculations are a first step toward a realistic model of blood flow in the venous microcirculation.

AB - Available in vitro and in vivo experimental observations suggest that red cell aggregation and blood vessel geometry are important determinants of the flow characteristics of blood in venules. However, no consistent relationship has been observed between red blood cell aggregation and vascular resistance. The present work attempts to understand this relationship by evaluating computationally the effect of red cell aggregation on the flow characteristics of blood in a converging vessel bifurcation. The proposed mathematical model considers blood as a two-phase continuum, with a central core region of concentrated red cell suspension that is surrounded by a layer of plasma adjacent to the vessel wall. In the central core region, blood is described by Quemada's non-Newtonian rheological model, in which local viscosity is a function of both the local hematocrit and a structural parameter that is related to the size of red blood cell aggregates. Fluids from the two feeding branches are immiscible, which results in a stratified multiphase flow in the collecting venule. Calculations predict a complex, three-dimensional pattern of blood flow and generally nonaxisymmetric distribution of velocity, hematocrit, and shear stress in the collecting venule. The calculations are a first step toward a realistic model of blood flow in the venous microcirculation.

KW - Hemorheology

KW - Mathematical model

KW - Quemada model

KW - Venous microcirculation

UR - http://www.scopus.com/inward/record.url?scp=0031035940&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0031035940&partnerID=8YFLogxK

M3 - Article

C2 - 9124728

AN - SCOPUS:0031035940

VL - 25

SP - 135

EP - 153

JO - Annals of Biomedical Engineering

JF - Annals of Biomedical Engineering

SN - 0090-6964

IS - 1

ER -