A fluid actuator (10, 410) for influencing a flow along a flow surface, particularly by pulsating ejection of a fluid flowing through the fluid actuator (10, 410), comprising - a multiplicity of outlet devices (20, 420) each having at least two outlet openings (24a, 24b, 422a, 422b) for ejection of the fluid and at least two corresponding outlet lines (22a, 22b) merging into the outlet openings (24a, 24b, 422a, 422b), - at least two interaction chambers which are in fluid-communicating connection with separate outlet openings (24a, 24b, 424a, 424b) via respective separate outlet lines (22a, 22b, 422a, 422b) and which comprise one flow dividing device each in each interaction chamber for dividing the flows into the outlet lines (22a, 22b, 422a, 422b), which flows merge from a feed line into the interaction chambers, and - a common control pressure varying device (60, 460) comprising a control flow dividing device (66, 466), - wherein control lines (62a, 62b) for mutually influencing the flow are connected to the control flow dividing device (66, 466), which control lines (62a, 62b) comprise branchings merging via corresponding control openings (64a, 64b) into all of the interaction chambers so as to provide respective different control pressures there by the control lines (62a, 62b) supplying into the at least two interaction chambers fluid at respective different control pressures, and - wherein each control line (62a, 62b) comprises a feedback line (72a, 72b, 472a, 472b) merging into the control flow dividing device (66, 466), so that if a fluid flow is supplied into the control flow dividing device (66, 466), an alternating control flow from one respective control line (62a, 62b) is brought about so as to alternatingly bring about the flow of the fluid from the feed line at least majoritarily into a respective one of the outlet lines (22a, 22b, 422a, 422b) and, thus, a pulsating flow in the outlet lines (22a, 22b, 422a, 422b). - a multiplicity of outlet devices (20, 420) each having at least two outlet openings (24a, 24b, 422a, 422b) for ejection of the fluid and at least two corresponding outlet lines (22a, 22b) merging into the outlet openings (24a, 24b, 422a, 422b), - at least two interaction chambers which are in fluid-communicating connection with separate outlet openings (24a, 24b, 424a, 424b) via respective separate outlet lines (22a, 22b, 422a, 422b) and which comprise one flow dividing device each in each interaction chamber for dividing the flows into the outlet lines (22a, 22b, 422a, 422b), which flows merge from a feed line into the interaction chambers, and - a common control pressure varying device (60, 460) comprising a control flow dividing device (66, 466), - wherein control lines (62a, 62b) for mutually influencing the flow are connected to the control flow dividing device (66, 466), which control lines (62a, 62b) comprise branchings merging via corresponding control openings (64a, 64b) into all of the interaction chambers so as to provide respective different control pressures there by the control lines (62a, 62b) supplying into the at least two interaction chambers fluid at respective different control pressures, and - wherein each control line (62a, 62b) comprises a feedback line (72a, 72b, 472a, 472b) merging into the control flow dividing device (66, 466), so that if a fluid flow is supplied into the control flow dividing device (66, 466), an alternating control flow from one respective control line (62a, 62b) is brought about so as to alternatingly bring about the flow of the fluid from the feed line at least majoritarily into a respective one of the outlet lines (22a, 22b, 422a, 422b) and, thus, a pulsating flow in the outlet lines (22a, 22b, 422a, 422b). - wherein control lines (62a, 62b) for mutually influencing the flow are connected to the control flow dividing device (66, 466), which control lines (62a, 62b) comprise branchings merging via corresponding control openings (64a, 64b) into all of the interaction chambers so as to provide respective different control pressures there by the control lines (62a, 62b) supplying into the at least two interaction chambers fluid at respective different control pressures, and - wherein each control line (62a, 62b) comprises a feedback line (72a, 72b, 472a, 472b) merging into the control flow dividing device (66, 466), so that if a fluid flow is supplied into the control flow dividing device (66, 466), an alternating control flow from one respective control line (62a, 62b) is brought about so as to alternatingly bring about the flow of the fluid from the feed line at least majoritarily into a respective one of the outlet lines (22a, 22b, 422a, 422b) and, thus, a pulsating flow in the outlet lines (22a, 22b, 422a, 422b).