Abstract:

ESDU 83042 presents methods for estimating spray 'envelopes' that define the height, width, shape and location of the following plumes generated by aircraft-type tyres running in water or slush: side-spray plumes from a single tyre (without or with chines), side-spray plumes from the outer edges of side-by-side tyre configurations (without or with chines), and centre-spray plumes for side-by-side tyre configurations. A single lateral row of more than two tyres is treated as a combination of the last two cases. For multiple-row configurations, such as a 'dual tandem' arrangement of four tyres, only the side-spray plumes from the outer edges of the leading tyres should be considered. Spray from between the leading tyres is likely to impinge on the undercarriage struts, mechanisms and trailing tyres (see ESDU 11004). The main applications of the data are to predict the likelihood of spray ingestion into engine intakes or impingement on such airframe components as flaps, sensors, antennae or surface joints where delamination might result, and in the prediction of forces due to impingement of spray on the airframe (see ESDU 98001 for estimation on skin-friction drag). The likely ranges of tyre inflation pressure and deflection, water or slush depth, and aircraft ground speed are covered. Advice is given on the influences on spray plume development of a number of aircraft and operational factors, and an estimation method for the effect of cross winds is included.