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Propagation of non-linear transient pressures through fresh and sea water / Gerald Muller in Journal of hydraulic research, Vol. 46 extra issue (2008) 

Public ISBD [article]  in Journal of hydraulic research > Vol. 46 extra issue (2008) . - p. 87-95 Titre : Propagation of non-linear transient pressures through fresh and sea water Titre original : Propagation de pressions transitoires non linéaires en eau douce et eau de mer Type de document : texte imprimé Auteurs : Gerald Muller, Auteur ; Peter Geisenhainer, Auteur ; Guido Wolters, Auteur Article en page(s) : p. 87-95 Note générale : Hydraulique Résumé en Français Langues : Anglais (eng) Mots-clés : Pressure  propagation  Cavitation  Fresh  water  Sea  water  Coastal  structures Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : The propagation of pressures generated by wave or jet impact into water filled cracks and fissures can create internal bursting pressures and resulting damages in structures such as blockwork breakwaters or coastal rock cliffs. Experimental investigations of pressure pulse propagation showed that the pressure pulses travelled as elastic waves in a water–air mixture inside of the cracks. Most previous experimental investigations were conducted at small scale, with near linear air compressibility. In reality, pressures will be well above atmospheric pressure so that non-linear effects can be expected. A series of drop tests was conducted to investigate the characteristics of pressure pulse propagation in the non-linear range of air compressibility in fresh and sea water. It was found that with pressure magnitudes exceeding approximately 100 kPa, the pulses become distinctly non-linear, with steep and short peaks and long, shallow troughs. The speed of propagation in fresh water ranged from 300 to 400 m/s, indicating air contents of 0.11 to 0.07% air. In sea water, the speed of propagation reached 290 m/s, indicating a slightly larger resident air content of 0.12%. Cavitation occurred and was accompanied in fresh water by short pressure bursts, which could not be observed in sea water. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.journalhydraulicresearch.com [article] Propagation of non-linear transient pressures through fresh and sea water = Propagation de pressions transitoires non linéaires en eau douce et eau de mer [texte imprimé] / Gerald Muller, Auteur ; Peter Geisenhainer, Auteur ; Guido Wolters, Auteur . - p. 87-95. Hydraulique Résumé en Français Langues : Anglais (eng) in Journal of hydraulic research > Vol. 46 extra issue (2008) . - p. 87-95 Mots-clés : Pressure  propagation  Cavitation  Fresh  water  Sea  water  Coastal  structures Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : The propagation of pressures generated by wave or jet impact into water filled cracks and fissures can create internal bursting pressures and resulting damages in structures such as blockwork breakwaters or coastal rock cliffs. Experimental investigations of pressure pulse propagation showed that the pressure pulses travelled as elastic waves in a water–air mixture inside of the cracks. Most previous experimental investigations were conducted at small scale, with near linear air compressibility. In reality, pressures will be well above atmospheric pressure so that non-linear effects can be expected. A series of drop tests was conducted to investigate the characteristics of pressure pulse propagation in the non-linear range of air compressibility in fresh and sea water. It was found that with pressure magnitudes exceeding approximately 100 kPa, the pulses become distinctly non-linear, with steep and short peaks and long, shallow troughs. The speed of propagation in fresh water ranged from 300 to 400 m/s, indicating air contents of 0.11 to 0.07% air. In sea water, the speed of propagation reached 290 m/s, indicating a slightly larger resident air content of 0.12%. Cavitation occurred and was accompanied in fresh water by short pressure bursts, which could not be observed in sea water. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.journalhydraulicresearch.com