activity are both shear producing processes that differ only in their degree of orientation on a fairly large scale that is a scale that is large compared to the size of individual fibers oriented shear is shear flow having a distinct and recognizable pattern in the undrained fiber suspension cross direction u201c cd u201d oriented shear improves both sheet formation and test the primary mechanism for cd shear on paper machines that do not shake is the creation collapse and subsequent recreation of a well defined machine direction u201c md u201d orientation in the paper fiber stock this can be done either by directing the flow in the headbox such that the jet wire interaction results in a large cd orientation or achieve the same result by facilitating predetermined drainage which directs the flow sideways the acoustic section is composed of piezoelectric ceramic transducers mounted to generate a propagating ultrasonic wave field upon excitation transducers 34 36 and 38 and optimally absorbers are removable and easily replaceable both the flow development and the acoustic sections have similar rectangular cross sections one dimension is e g several centimeters corresponding to the width of transducers and the normal dimension is adjustable mechanical separation is provided with an adjustable mechanical foil assembly the narrow band single element transducers 34 36 and 38 were designed to resonate.