Combined method of calculating supersonic ideal-gas flow over a wing with a supersonic blunt leading edge

Estimates for pressures on the surface of a given delta wing at zero incidence in a steady uniform stream of air are obtained by numerically integrating two semi-characteristic forms of equations which govern the inviscid supersonic flow of an ideal gas with constant specific heats. In one form of the equations coordinate surfaces are fixed in space so that the surface of the wing, which has round sonic leading edges, is a coordinate surface. In the other, two families of coordinates are chosen to be stream-surfaces. For each form of the equations, a finite difference method has been used to compute the supersonic flow around the wing. Convergence of the numerical results, as the mesh is refined, is slow near the leading edge of the wing and an extrapolation procedure is used to predict limiting values for the pressures on the surface of the wing at two stations where theoretical and experimental results have been given earlier by another worker. At one station differences between the results given here and the results given earlier are significant. The two methods used here produce consistent values for the pressures on the surface of the wing and, on the basis of this numerical evidence together with other cited numerical results, it is concluded that the pressures given here are close to the true theoretical values.

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Similarity of ideal gas flow at different scales

Science in China Series E ◽

10.1360/02ye0072 ◽

2003 ◽

Vol 46 (6) ◽

pp. 661 ◽

Cited By ~ 18

Author(s):

Moran WANG

Keyword(s):

Gas Flow ◽

Ideal Gas

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METODE PERHITUNGAN MASSA GAS CO2 YANG DISERAP FOTOBIOREAKTOR DENGAN PERSAMAAN GAS IDEAL

Jurnal Teknologi Lingkungan ◽

10.29122/jtl.v11i2.1208 ◽

2016 ◽

Vol 11 (2) ◽

pp. 239

Author(s):

Arif Dwi Santoso

Keyword(s):

Gas Flow ◽

Co2 Concentration ◽

Ideal Gas ◽

Gas Absorption ◽

Flow Diagram ◽

Measuring Instruments ◽

Continuous Systems ◽

Co2 Gas ◽

Method Of Calculation ◽

The Ideal

BPPT conducted the mass of CO2 gas calculation in the gas absorption experiments with phytoplankton cultivation in the photobioreaktor (FBR) batch and continous syatem using the ideal gas equation. This study stated that the method of calculation with the ideal gas equation is more simple and practical in providing data analysis compared with biomass methods. Some things to note in this method include good knowledge about the movement of the gas flow diagram of inputs and outputs FBR, an appropriate gas sampling, and accuracy of measuring instruments. The required data in the mass calculation of CO2 gas in a batch photobioreactor system was resultant CO2 concentration during measurement. Meanwhile in a continuous systems, the requireddata was CO2 concentration at the reactor input and output , the rate and duration of the injection gas.Keywods : massa gas CO2, dry weight, ideal gas formula

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Incompressible flow calculations of blunt leading edge separation for a 53 degree swept diamond wing (Invited)

53rd AIAA Aerospace Sciences Meeting ◽

10.2514/6.2015-0065 ◽

2015 ◽

Cited By ~ 5

Author(s):

Michel Visonneau ◽

Emmanuel Guilmineau ◽

Serge L. Toxopeus

Keyword(s):

Incompressible Flow ◽

Leading Edge ◽

Edge Separation ◽

Blunt Leading Edge

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Gas-Driven Fracture Propagation

Journal of Applied Mechanics ◽

10.1115/1.3157729 ◽

1981 ◽

Vol 48 (4) ◽

pp. 757-762 ◽

Cited By ~ 32

Author(s):

R. H. Nilson

Keyword(s):

Gas Flow ◽

Oil And Gas ◽

Elementary Function ◽

Separation Of Variables ◽

Pressure Ratio ◽

Leading Edge ◽

Late Time ◽

Shooting Methods ◽

Uniform Compression ◽

Penetration Length

A one-dimensional gas-flow drives a wedge-shaped fracture into a linearly elastic, impermeable half space which is in uniform compression, σ∞, at infinity. Under a constant driving pressure, p0, the fracture/flow system accelerates through a sequence of three self-similar asymptotic regimes (laminar, turbulent, inviscid) in which the fracture grows like an elementary function of time (exponential, near-unity power, and linear, respectively). In each regime, the transport equations are reducible under a separation-of-variables transformation. The integro-differential equations which describe the viscous flows are solved by iterative shooting methods, using expansion techniques to accomodate a zero-pressure singularity at the leading edge of the flow. These numerical results are complemented by an asymptotic analysis for large pressure ratio (N = p0/σ∞ → ∞) which exploits the disparity between the fracture length and penetration length of the flow. Since the seepage losses to a surrounding porous medium are shown to be negligable in the late-time long-fracture limit, the results have application to geologic problems such as: containment evaluation of underground nuclear tests, stimulation of oil and gas wells, and permeability enhancement prior to in situ combustion processes.

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Impact of Heterogeneity on the Transient Gas Flow Process in Tight Rock

Energies ◽

10.3390/en12183559 ◽

2019 ◽

Vol 12 (18) ◽

pp. 3559 ◽

Cited By ~ 1

Author(s):

Jia ◽

Tsau ◽

Barati ◽

Zhang

Keyword(s):

History Matching ◽

Gas Flow ◽

Preferential Flow ◽

Early Stage ◽

Ideal Gas ◽

Flow Path ◽

Flow Process ◽

The Core ◽

Porosity And Permeability ◽

Preferential Flow Path

There exits a great challenge to evaluate the flow properties of tight porous media even at the core scale. A pulse-decay experiment is routinely used to measure the petrophysical properties of tight cores including permeability and porosity. In this study, 5 sets of pulse-decay experiments are performed on a tight heterogeneous core by flowing nitrogen in the forward and backward directions under different pressures under pore pressures approximately from 100 psi to 300 psi. Permeability values from history matching are from about 300 nD to 600 nD which shows a good linear relationship with the inverse of pore pressure. A preferential flow path is found even when the microcrack is absent. The preferential path causes different porosity values using differential initial upstream and downstream pressure. In addition, the porosity values calculated based on the forward and backward flow directions are also different, and the values are about 1.0% and 2.3%, respectively, which is the primary novelty of this study. The core heterogeneity effect significantly affects the very early stage of pressure responses in both the upstream and downstream but the permeability values are very close in the late-stage experiment. We proposed that that there are two reasons for the preferential flow path: the Joule–Thomson effect for non-ideal gas and the core heterogeneity effect. Based on the finding of this study, we suggest that very early pressure response in a pulse-decay experiment should be closely examined to identify the preferential flow path, and failure to identify the preferential flow path leads to significant porosity and permeability underestimation.

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Effects of leading-edge bevel angle on the aerodynamic forces of a non-slender 50° delta wing

The Aeronautical Journal ◽

10.1017/s0001924000000828 ◽

2005 ◽

Vol 109 (1098) ◽

pp. 403-407 ◽

Cited By ~ 7

Author(s):

J. J. Wang ◽

S. F. Lu

Keyword(s):

Delta Wing ◽

Lift Coefficient ◽

Leading Edge ◽

Relative Thickness ◽

Aerodynamic Performances ◽

Stall Angle ◽

Drag Ratio ◽

Low Speed Wind Tunnel ◽

Lift To Drag Ratio ◽

Blunt Leading Edge

Abstract The aerodynamic performances of a non-slender 50° delta wing with various leading-edge bevels were measured in a low speed wind tunnel. It is found that the delta wing with leading-edge bevelled leeward can improve the maximum lift coefficient and maximum lift to drag ratio, and the stall angle of the wing is also delayed. In comparison with the blunt leading-edge wing, the increment of maximum lift to drag ratio is 200%, 98% and 100% for the wings with relative thickness t/c = 2%, t/c = 6.7% and t/c = 10%, respectively.

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