Biofluid Flow and Heat Transfer

2nd EditionInternational audienceMajor moving biological fluids, or biofluids, are blood and air that cooperate to bring oxygento the body’s cells and eliminate carbon dioxide produced by these cells. Blood is conveyed ina closed network composed of 2 circuits in series — the systemic and pulmonary circulation—, each constituted by arteries, capillaries, and veins, under the synchronized action of theleft and right cardiac pumps, respectively. Air is successively inhaled from and exhaled to theatmosphere through the airway openings (nose and/or mouth). In the head, blood generatesthe cerebrospinal fluid in choroid plexi of all compartments of the ventricular system andreceives it in arachnoid villi. Other biofluids are either secreted, such as bile from the liverand breast milk that both transport released substances with specific tasks, or excreted,such as urine from kidneys or sweat from skin glands that both convey useless materials andwaste produced by the cell metabolism. In addition to the convective transport, peristalsis,which results from the radial contraction and relaxation of mural smooth muscles, propelsthe content of the lumen of the muscular bioconduit (e.g., digestive tract) in an anterogradedirection.Blood circulation and air flow in the respiratory tract are widely explored because oftheir vital functions. Note that inhaled air is transported through the respiratory tract bytwo processes: convection down to bronchioles and diffusion down to pulmonary alveoli.1Furthermore, investigations of these physiological flows in deformable bioconduits give riseto models such as the Starling resistance that themselves become object of new study fieldsin physics and mechanics (e.g., collapsible tubes) as well as of new developments in math-ematical modeling and scientific computing. Whereas fluid–structure interaction problemsin aeronautics and civil engineering deal with materials of distinct properties, blood streamand vessel wall correspond to two domains of nearly equal physical properties, as both bloodand vessels have densities close to that of water. New processing strategies must then beconceived