Abstract:Interactions between the boundary layer and two successive incident shock waves (ISWs) often occur in the supersonic mixed-compression inlets. However, the flow mechanism involved in such interactions has been studied rarely. In this study, we investigate experimentally and analytically the turbulent boundary layer separation flow induced by the single ISW and dual ISWs at the identical total deflection angles in a Mach 2.73 flow. Schlieren photography, wall pressure measurement and surface oil-flow visualisat… Show more
“…The test model is the same as that in Li et al. (2022), as depicted in figure 2. The shock generator (SG) had a double-wedge configuration to induce two ISWs.…”
Section: Experimental Methodologymentioning
confidence: 99%
“…Further details of the measurement of TBL parameters are provided in Li et al. (2022). Figure 2.( a ) Test model in the wind tunnel.…”
Section: Experimental Methodologymentioning
confidence: 99%
“…This paper is a sequel of the study of Li et al. (2022). In the current study, we experimentally examine two groups of dual-ISWTBLIs with two deflection angles of (7, 5) and (5, 7); for each group, five experiments are conducted to quantitatively investigate the effect of shock wave distance on the separation length.…”
Section: Introductionmentioning
confidence: 90%
“…Recently, experimental studies of dual-incident SWTBLIs (dual-ISWTBLIs) indicated that the distance between two ISWs significantly affects the separation configuration (Li et al. 2020, 2022). These studies reported that the dual-ISWTBLIs have three typical flow patterns.…”
Section: Introductionmentioning
confidence: 99%
“…Moreover, Li et al. (2022) provided an analysis of the separation length scaling for type 1 dual-ISWTBLIs. Based on the re-established normalised parameters, the datasets of type 1 dual-ISWTBLIs can fall close to the trend line reported in a study of single-ISWTBLIs and CRSWTBLIs by Souverein et al.…”
In this study, the length scaling for the boundary layer separation induced by two incident shock waves is experimentally and analytically investigated. The experiments are performed in a Mach 2.73 flow. A double-wedge shock generator with two deflection angles (
$\alpha _1$
and
$\alpha _2$
) is employed to generate two incident shock waves. Two deflection angle combinations with an identical total deflection angle are adopted: (
$\alpha _1 = 7^\circ$
,
$\alpha _2 = 5^\circ$
) and (
$\alpha _1 = 5^\circ$
,
$\alpha _2 = 7^\circ$
). For each deflection angle combination, the flow features of the dual-incident shock wave–turbulent boundary layer interactions (dual-ISWTBLIs) under five shock wave distance conditions are examined via schlieren photography, wall-pressure measurements and surface oil-flow visualisation. The experimental results show that the separation point moves downstream with increasing shock wave distance (
$d$
). For the dual-ISWTBLIs exhibiting a coupling separation state, the upstream interaction length (
$L_{int}$
) of the separation region approximately linearly decreases with increasing
$d$
, and the decrease rate of
$L_{int}$
with
$d$
increases with the second deflection angle under the condition of an identical total deflection angle. Based on control volume analysis of mass and momentum conservations, the relation between
$L_{int}$
and
$d$
is analytically determined to be approximately linear for the dual-ISWTBLIs with a coupling separation region, and the slope of the linear relation obtained analytically agrees well with that obtained experimentally. Furthermore, a prediction method for
$L_{int}$
of the dual-ISWTBLIs with a coupling separation region is proposed, and the relative error of the predicted
$L_{int}$
in comparison with the experimental result is
$\sim$
10 %.
“…The test model is the same as that in Li et al. (2022), as depicted in figure 2. The shock generator (SG) had a double-wedge configuration to induce two ISWs.…”
Section: Experimental Methodologymentioning
confidence: 99%
“…Further details of the measurement of TBL parameters are provided in Li et al. (2022). Figure 2.( a ) Test model in the wind tunnel.…”
Section: Experimental Methodologymentioning
confidence: 99%
“…This paper is a sequel of the study of Li et al. (2022). In the current study, we experimentally examine two groups of dual-ISWTBLIs with two deflection angles of (7, 5) and (5, 7); for each group, five experiments are conducted to quantitatively investigate the effect of shock wave distance on the separation length.…”
Section: Introductionmentioning
confidence: 90%
“…Recently, experimental studies of dual-incident SWTBLIs (dual-ISWTBLIs) indicated that the distance between two ISWs significantly affects the separation configuration (Li et al. 2020, 2022). These studies reported that the dual-ISWTBLIs have three typical flow patterns.…”
Section: Introductionmentioning
confidence: 99%
“…Moreover, Li et al. (2022) provided an analysis of the separation length scaling for type 1 dual-ISWTBLIs. Based on the re-established normalised parameters, the datasets of type 1 dual-ISWTBLIs can fall close to the trend line reported in a study of single-ISWTBLIs and CRSWTBLIs by Souverein et al.…”
In this study, the length scaling for the boundary layer separation induced by two incident shock waves is experimentally and analytically investigated. The experiments are performed in a Mach 2.73 flow. A double-wedge shock generator with two deflection angles (
$\alpha _1$
and
$\alpha _2$
) is employed to generate two incident shock waves. Two deflection angle combinations with an identical total deflection angle are adopted: (
$\alpha _1 = 7^\circ$
,
$\alpha _2 = 5^\circ$
) and (
$\alpha _1 = 5^\circ$
,
$\alpha _2 = 7^\circ$
). For each deflection angle combination, the flow features of the dual-incident shock wave–turbulent boundary layer interactions (dual-ISWTBLIs) under five shock wave distance conditions are examined via schlieren photography, wall-pressure measurements and surface oil-flow visualisation. The experimental results show that the separation point moves downstream with increasing shock wave distance (
$d$
). For the dual-ISWTBLIs exhibiting a coupling separation state, the upstream interaction length (
$L_{int}$
) of the separation region approximately linearly decreases with increasing
$d$
, and the decrease rate of
$L_{int}$
with
$d$
increases with the second deflection angle under the condition of an identical total deflection angle. Based on control volume analysis of mass and momentum conservations, the relation between
$L_{int}$
and
$d$
is analytically determined to be approximately linear for the dual-ISWTBLIs with a coupling separation region, and the slope of the linear relation obtained analytically agrees well with that obtained experimentally. Furthermore, a prediction method for
$L_{int}$
of the dual-ISWTBLIs with a coupling separation region is proposed, and the relative error of the predicted
$L_{int}$
in comparison with the experimental result is
$\sim$
10 %.
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