Sonic-supersonic solutions for a reactive transonic small disturbance model

2021 ◽  
pp. 125380
Author(s):  
Ping Lv ◽  
Yanbo Hu
Keyword(s):  
Small Disturbance ◽  
Disturbance Model

A transonic small-disturbance model for the propagation of weak shock waves in heterogeneous gases

2001 ◽  
Vol 429 ◽  
pp. 255-280 ◽  
Author(s):  
THOMAS E. GIDDINGS ◽  
ZVI RUSAK ◽  
JACOB FISH
Keyword(s):  
Shock Waves ◽  
Heterogeneous Media ◽  
Weak Shock ◽  
Small Disturbance ◽  
Gaseous Media ◽  
The Media ◽  
Observed Behaviour ◽  
Disturbance Model ◽  
Interaction Phenomena ◽  
Good Agreement

The interaction of weak shock waves with small heterogeneities in gaseous media is studied. It is first shown that various linear theories proposed for this problem lead to pathological breakdowns or singularities in the solution near the wavefront and necessarily fail to describe this interaction. Then, a nonlinear small-disturbance model is developed. The nonlinear theory is uniformly valid and accounts for the competition between the near-sonic speed of the wavefront and the small variations of vorticity and sound speed in the heterogeneous media. This model is an extension of the transonic small-disturbance problem, with additional terms accounting for slight variations in the media. The model is used to analyse the propagation of the sonic-boom shock wave through the turbulent atmospheric boundary layer. It is found that, in this instance, the nonlinear model accounts for the observed behaviour. Various deterministic examples of interaction phenomena demonstrate good agreement with available experimental data and explain the main observed phenomena in Crow (1969).

A Small Disturbance Model for Transonic Flow of Pure Steam With Condensation

2018 ◽  
Vol 141 (3) ◽  
Author(s):  
Akashdeep Singh Virk ◽  
Zvi Rusak
Keyword(s):  
Mass Fraction ◽  
Nonlinear Partial Differential Equation ◽  
Inviscid Flow ◽  
Droplet Growth ◽  
Small Disturbance ◽  
Flow Equations ◽  
Liquid Saturation ◽  
Nonequilibrium Condensation ◽  
Disturbance Model ◽  
Pure Steam

A small-disturbance model to study transonic steady condensing flow of pure steam around a thin airfoil is developed. Water vapor thermodynamics is described by the perfect gas model and its dynamics by the compressible inviscid flow equations. Classical nucleation and droplet growth theory for homogeneous and nonequilibrium condensation is used to compute the condensate mass fraction. The model is derived from an asymptotic analysis of the flow and condensation equations in terms of the proximity of upstream flow Mach number to 1, the small thickness ratio of airfoil, the small quantity of condensate, and the small angle-of-attack. The flow field may be described by a nonhomogeneous and nonlinear partial differential equation along with a set of four ordinary differential equations for calculating condensate mass fraction. The analysis provides a list of similarity parameters that describe the flow physics. A numerical scheme, which is composed of Murman and Cole's algorithm for the computation of flow parameters and Simpson's integration method for calculation of condensate mass fraction, is applied. The model is used to analyze the effects of heat release due to condensation on the aerodynamic performance of airfoils operating in steam at high temperatures and pressures near the vapor–liquid saturation dome.

A small-disturbance model of transonic combustion

2007 ◽  
Vol 12 (1) ◽  
pp. 93-113 ◽  
Author(s):  
Z. Rusak ◽  
J.-C. Lee ◽  
J. J. Choi
Keyword(s):  
Small Disturbance ◽  
Disturbance Model

Research on Improved Small-Disturbance Model of Doubly-Fed Wind Generator

2014 ◽  
Vol 852 ◽  
pp. 692-696
Author(s):  
Gan Li ◽  
Hua Zhang ◽  
Wei Wei ◽  
Le Chang
Keyword(s):  
Control Strategies ◽  
Oscillation Mode ◽  
Small Disturbance ◽  
Wind Generator ◽  
Proposed Model ◽  
Electromagnetic Characteristics ◽  
Simulation Results ◽  
Disturbance Model ◽  
Doubly Fed ◽  
Mechanical Rotation

An improved small-disturbance model of the doubly-fed wind generator is proposed in this paper. In comparison to traditional small-disturbance models, the proposed model comprehensively considers the mechanical rotation of the wind turbine, the shaft transmission in the gear box, the electromagnetic characteristics of the induction generator, as well as the control strategy for both rotor and stator, so that it is able to precisely describe the oscillation mode of the wind generator that is integrated into the power grid. In case studies, simulation results have verified the effectiveness of the proposed model, and different control strategies are applied to the doubly-fed wind generator to investigate their influences on its oscillation mode.

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