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A device was designed to provide a "square" pulse of blood flow into the arterial system. Pulses were injected into the carotid artery of the rabbit during transient cardiac arrest. Analysis of pressure response curves generated by the flow provides information as to the state of the arterial tree. With certain assumptions it is possible to estimate from these curves lumped values of peripheral resistance, critical closing pressure, and arterial compliance. In a series of 12 rabbits the mean value of peripheral resistance was found to be 0.21 +/- 0.7 mmHg-ml-1-min and critical closing pressure was estimated to be 23.6 +/- 3.8 mmHg. This method gives two possible values for arterial compliance 0.036 +/- 0.010 and 0.055 +/- 0.010 ml-mm-1 based, respectively, on the rise and decay curves of the pressure response. The theory and limitations of the method are discussed. The use of the method is illustrated in following the response to increased PCO2 and hemorrhage.

An array of circular synthetic jets has been used to control the flow around a NACA0015 wing, at a chord Reynolds number of 8.9  10 5 and an incidence angle of 14. The onset of flow separation was delayed, and both the lift and drag characteristics of the wing were improved through the use of the flow control system. The forcing frequency was decoupled from the dynamic response of the actuators themselves by means of amplitude modulation, and a range of forcing frequencies was tested. The results demonstrated that successful control could be achieved with significantly reduced input power requirements, improving net efficiency. The effectiveness of the flow control system was also shown to be fairly independent of the frequency when used in this way.

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