McCullough James R.
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Technical ReportSummary of current meter operations in 1968(Woods Hole Oceanographic Institution, 1969-03) McCullough, James R. ; Tupper, George H.This report describes work done with Geodyne current meters and wind recorders during 1968. Techniques for testing instruments prior to use at sea, instrument performance at sea and instrument changes evolved during the year are discussed.
Technical ReportMoored acoustic travel time (ATT) current meters : evolution, performance, and future designs(Woods Hole Oceanographic Institution, 1979-12) McCullough, James R. ; Graeper, WilhelmNew laboratory measurements and numeric model studies show the present folded-path ATT current meters are stable and sensitive, but are not well suited for mean flow observations in surface gravity waves. Alternate designs which reduce unwanted wake effects are proposed. ATT flowmeter history, principles of acoustic flow sensors, mean flow near cylinders, and the need for linear flow sensors are reviewed.
Technical ReportVector averaging current meter speed calibration and recording technique(Woods Hole Oceanographic Institution, 1975-09) McCullough, James R.Equations 1-4 summarize the rotor calibration used at Woods Hole Oceanographic Institution for the VACM. A discussion of the instrumental and test details used to derive these equations follows. A list of other VACM documents and related bibliography is included.
Technical ReportNear-surface ocean current sensors : problems and performance(Woods Hole Oceanographic Institution, 1979-12) McCullough, James R.When current meters are used to measure mean horizontal currents in surface gravity waves, immunity to the vertical component of flow is important, even though the net vertical flow averages to zero and is normal to the desired horizontal components. A technique is presented for estimating the magnitude of the errors introduced by imperfect rejection of the off-axis flows (cross-talk) from laboratory measurements of the current meter "vertical-cosine-response." The predicted dynamic response is shown to compare favorably with laboratory measurements. The measured steady state vertical-cosine-response functions for several practical current sensors are summarized and used to estimate the magnitude of wave-induced errors in horizontal mean current measurements. A new dye technique for evaluating near-surface current meter performance in waves is shown.