Hypersonic Rarefied Flow Research Articles

球状物体まわりの稀薄極超音速流

The present paper is concerned with shockwave and viscous-layer structures ahead of a blunt body in a rarefied hypersonic flow. The analysis is within the framework of the continuum theory, based on the two-layer flow model.The solution for viscous layer is found to be matched with the solution for shock wave at the outer edge of viscous layer or at the downstream limit of shock wave. The profiles of flow variables, thus obtained, across the shock wave and viscous layer are found to be in a fairly good agreement with the results obtained, respectively, by LEVINSKY-YOSHIHARA and by KAO based on the method of full numerical integration for the NAVIER-STOKES equations. Furthermore some of characteristic features of the flow behavior due to rarefaction effects have been clarified by the analysis.

A theoretical model for the sharp flat plate in rarefied hypersonic flow.

Rarefied hypersonic flow model for sharp flat plate in strong interaction regimes, discussing inviscid and viscous shock and merged layers subregimes

An experimental model for the sharp flat plate in rarefied hypersonic flow.

An experimental model for the sharp flat plate in rarefied hypersonic flow.

An experimental study of hypersonic rarefied flow over a blunt body.

An experimental study of hypersonic rarefied flow over a blunt body.

Pressure distributions on sharp cones in rarefied hypersonic flow.

Pressure distributions on sharp cones in rarefied hypersonic flow.

Hypersonic rarefied flow past the sharp leading edge of a flat plate.

Hypersonic rarefied flow past the sharp leading edge of a flat plate.

Influence of real gas effects on the hypersonic rarefied flow near the sharp leading edge of a thin plate

In this paper are presented the results of an investigation of the induced pressure distribution on a thin plate with a sharp leading edge placed in supersonic rarefaction flow. The research was carried out in the low-density wind tunnel under the following conditions in the incident flow 5·7 ⩽ M ⩽ 14, 30 ⩽ Re ∞/mm ⩽ 600. The results obtained show that as one approaches sufficiently closely to the leading edge, the strong interaction theory no longer agrees with the experimental data and as χ = [(μ 3 ∞√C ∞)/√Re x∞ increases, the induced pressure on the plate approaches a constant value starting with χ> χ lim , where χ lim depends upon the Mach number. For example, χ lim is similar to 8 at the Mach number 5·7. The most characteristic of the induced pressure distribution is the deviation of the induced pressure from the strong interaction theory as rarefaction increases. There is a strong decrease in Δ P/ χP ∞ for [( μ ∞√ C ∞)/√ Re x∞ ] > 0·2.

Aerodynamic characteristics of rectangular plates in a hypersonic rarefied gas flow

To determine optimal wing shapes in a viscous hypersonic flow, experimental studies were made of the aerodynamic characteristics of rectangular plates with equal areas s and various values of the aspect ration k and thickness d at free-stream M = 5.15, Reynolds number R ~ 2.102, and angles of attack a varying from 0 to 40*. The aspect ratio k of the plates varies in the range 0.1-9, and their relative thickness 6 = d / ] / ' s varied in the range 0.025-0.16. It was found that, at fixed values of the area and thickness of the rectangular plate, the variation of its maximal lift/drag ratio K m (X) in the range of angles of attack investigated has a maximum in the region of values k: 0.4-0.8.

Shock wave shapes on a sharp flat plate in rarefied hypersonic flow.

Shock wave shapes on a sharp flat plate in rarefied hypersonic flow.

Impact pressure behavior in rarefied hypersonic flow

I is well established that, as the rarefied flow regime is entered, the pressure sensed by blunt impact probes under constant stream conditions but with decreasing probe Reynolds number Rem will first decrease and then gradually rise. The rising pressure trend continues with decreasing Re^ until free molecule flow conditions are reached where the indicated pressure may be several times greater than the inviscid continuum impact pressure. However, the behavior of blunt-body impact pressures as a function of the pertinent flow parameters has not been quantitatively determined throughout the complete rarefied flow regimes. The present investigation was conducted for the purposes of 1) extending the knowledge of the governing flow parameters further into the rarefied flow regime, 2) gaining a further insight of the mechanisms affecting the blunt-body impact pressure behavior, and 3) providing experimental data demonstrating the measurement characteristics of blunt impact pressure probes at low Reynolds numbers and elevated hypersonic Mach numbers.