From pressure fluctuations to dynamic loads on axisymmetric step flows with minimal number of kulites

Experimental analysis of the pressure–velocity correlations of external unsteady flow over rocket launchers

“…As it was previously shown [16,17], the main contribution of the load is held by the two first Fourier modes, in such a flow configuration. Then, in this study, the integrated load is computed thanks to these two modes by combining Eqs.…”

“…Based on the synchronous wall pressure measurements providing a detailed description of spatio-temporally varying side loads, it is useful to get this information from the transducers by integrating the pressure along the nozzle as follows [16]: where dS i is the elementary surface surrounding the ith sensor, N c is the number of pressure transducers, L is the streamwise length, r(x) is the nozzle radius at position x, n is the surface normal vector and ≡ indicates the equivalence operator in discrete space. In this work, the integrated load refers to the integration of wall pressure load all around the 8 rings of sensors (that is both on the nozzle and on the engine thermal protection).…”

“…where y and z are unitary vectors defined in Fig. 1, dS i is the elementary surface surrounding sensor i (see [16]) and m refer to the Fourier mode number (1 or 2). From a structural point of view, F 1 and F 2 have a different effect on the nozzle.…”

Wall Pressure and External Velocity Field Relation in Overexpanded Supersonic Jets

“…However, one of the great assets of their study is the fact that the authors placed their sensors in azimuthal arrays to isolate the anti-symmetric azimuthal mode, which is the only one responsible for side-loads creation. Previous attemps to isolate this azimuthal mode used only two sensors in the azimuthal direction [9,19], giving undersampled data in the azimuthal direction.…”

Passive Flow Control for the Load Reduction of Transonic Launcher Afterbodies

“…On the other hand, the reduced fluctuations at the longer momentum arm decrease the overall loads on the reattaching surface. Because of the limited number of pressure sensors in the model, it remains somewhat uncertain whether the overall dynamic loads could be reduced by the applied modifications [45]. However, the presented results indicate that the tested flow control devices could potentially be used to reduce mechanical loads on a space launcher's main engines nozzle during transonic flight.…”