Date of Award

Fall 1963

Document Type

Thesis - Restricted

Degree Name

Master of Science (MS)


Biomedical Engineering

First Advisor

Horgan, James D.

Second Advisor

Larks, Saul D.

Third Advisor

Stead, William W.


Pulmonary physiologists have long been aware of abnormalities of air flow as a basic defect in a variety of pulmonary diseases. Various methods of examination of airflow have frequently given incomplete information. Most of the approaches in the past have attempted to look on the bronchus as a simple rigid tube which conducted air when a pressure was applied to the air within the alveoli. But various clinical and theoretical studies have demonstrated that the bronchus is not rigid, nor is its behavior simple. The air flow which develops will be a function of the lung volume, characteristics of the surrounding tissues and the airway, the pressure within the thoracic cavity, and the airflow itself. Thus, an apparently simple system, is really quite complex, and might be better understood if a more theoretical approach were used. Such a theoretical approach to flow in the lung could treat air as any other fluid, and basic equations of fluid mechanics could be applied. Dr. Donald L. Fry of Bethesda, Md. had previously attempted this approach, but was quickly thwarted by the complexity of the equations. It seemed logical that a digital computer technique of numeric integration could be applied to these equations, and series of solutions could be developed. Thus the basic problem of the thesis became the development of a technique of integrating a set of equations describing fluid flow through a distensible tube, and the characteristics of the tube. The integration technique developed was subsequently tested by comparing solutions with data that Dr. Fry had published on a mechanical model he devised to test the limited mathematical manipulation he was able to achieve without a computer. It is the hope of the essayist that this will provide a stepping stone to the ultimate problem of describing the characteristics of airways to provide knowledge of the type, etiology, and degree of various disease states.



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