FLOW FIELD AND SCOURING EFFECTS OF STEADY AND PULSATlNG JETS IMPINGING ON A MOVABLE BED ETUDE DU CHAMP D'ECOULEMENT ET DES PHENOMENES D'AFFOUILLEMENT DES JETS CONTINUS ET PULSES A L'IMPACT SUR UN FOND MOBILE
نویسندگان
چکیده
The flow field and erosion pattern of continuous and pulsating impinging jets has been studied experimentally. The mean velocity field as well as turbulent and pulsation components, wall pressure and wall shear stress distr ibutions were investigated in an axisymmetric air jet impinging upon a rough wall. The results show how harmonic velocity pulsations at the nozzle affect both the mean and the turbulent flow field. Corresponding erosion tests with a vertical water jet impinging upon a uniform sand bed exhibited under certain conditions a greatly enhanced erosion rate. The increase in erosion capacity due to pulsation seems to be due to both the changes in the mean flow field and to the greatly increased lateral correlation of the velocity field in the impinging region.
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