Performance Of Waverider Research Articles

Stream-Surface Iteration-Based Flowfield Calculation Method for Pressure-Controllable Waverider Design

The performance of waveriders is greatly influenced by the wall pressure distribution. To achieve the goal of designing a waverider based on the complex two-dimensional pressure distribution, this study proposes a methodology called the stream-surface iteration-based flowfield calculation (SIFC) method. This method discretizes the three-dimensional flowfield with curved stream surfaces and approximates the flow around each point with a unique axisymmetric flow. Moreover, this method iteratively solves the shape of each stream surface and the corresponding flowfield to deal with ill-posed problems. To verify its effectiveness, the SIFC method was first applied to inversely solve the two external annular supersonic flowfields. Then, it was used for the waverider design. The computational fluid dynamics results showed that the relative error of the wall pressure was less than 2.6% for the annular supersonic flowfields. The wall pressure determines the geometric shapes and mechanical properties of waveriders. The pressure center of a waverider can be shifted by 12% of the length in the flow direction and 7.4% of the width in the crossflow direction by altering the input wall pressure. This shift will cause the waverider to produce more than 30% extra trim drag when cruising at the design Mach number.

Influence of Non-Uniform Bluntness on Aerodynamic Performance and Aerothermal Characteristics of Waverider

The waverider is widely used in hypersonic vehicles with its high aerodynamic performance, but due to the serious aerothermal environment, its sharp leading edge should be blunted. Circular blunt is one of the commonly used aerothermal characteristic protection methods. Circular blunt with larger diameter can reduce peak heat flux, but at the same time, it will lead to larger drag. The existing research shows that under the same blunt diameter in two-dimensions, the non-uniform blunt can reduce the peak heat flux by 20%, and the difference of drag is small. In this paper, the non-uniform blunt profile is applied to the three-dimensional waverider, and the influence of the non-uniform blunt profile on the aerothermal characteristic performance and aerodynamic performance of the waverider is studied, and the results are compared with those of circular blunt. The numerical simulation is used to compare and analyze the waverider under different angles of attack, flight altitudes, and Mach number. The results show that the peak heat flux of the waverider with non-uniform blunt reduces by about 17% compared with that with circular blunt under a small angle of attack range, Mach 2-10, and a flight altitude of 15–35 km. Meanwhile, when the blunt height/diameter is 20 mm, the aerodynamic performance difference between the two different blunt profiles does not exceed 3% within a 15 degrees angle of attack, Mach 2-10, and flight altitude of 15–35 km. The non-uniform blunt profile can be applied to the design of the three-dimensional waverider.

Investigation of aerodynamics education based on the waverider parameterized design procedure

This paper describes the development and coding of a design tool for waverider parameterization based on the Taylor-Maccoll equation and streamline tracing method. This tool, intended for undergraduates studying in the field of aerody-namics, illustrates the relationship among various parameters in terms of their effect on the aerodynamic performance of waverider models with the same freestream Mach number. The design procedure is evaluated and validated for multiple shock wave profiles and freestream Mach numbers, and is found to be in good agreement with the CFD results. For undergraduates studying aeronautical engineering, the suggested design tool offers an intuitive image of waverider cre-ation and a clear picture of the guiding principles of waveriders. By imposing a set of design criteria, the tool also gives students enough freedom to arrive at their own waverider shape.

Inverse Design of Hypersonic Waveriders with Variable Cross-Section Shock Waves

A new inverse design methodology for a variable cross-section shock waverider (VCSW) is proposed to extend the flexibility of waverider design based on the local-turning osculating cones method. The proposed waverider is designed to ride on the top of a variable cross-section shock wave, whose cross-sectional shape is an ellipse with different eccentricity ratios. The feasibility and effectiveness of this method are verified using inviscid computational fluid dynamics simulations. To investigate the influence of the eccentricity ratio on the shape and aerodynamic performance of waveriders, five VCSW cases with different eccentricity ratio distributions are derived and numerically analyzed in detail. The results demonstrate that the VCSW with an increasing eccentricity ratio along the streamwise direction has a larger volumetric efficiency but a smaller lift-to-drag ratio. There is a contradiction between the volumetric and aerodynamic performances, and the tradeoff should be considered in the design process. In addition, the growth rate of the eccentricity ratio along the streamwise direction is also an important factor to design VCSW, which can be used to improve the performance of hypersonic waverider vehicles.

Numerical study on aerodynamic performance of waverider with a new bluntness method

Abastrct The waverider is deemed the most promising configuration for hypersonic vehicle with its high lift-to-drag ratio at design conditions. However, considering the serious aero-heating protection, the sharp leading edge must be blunted. The existing traditional bluntness methods including the following two types: “reducing material method” and “adding material method”. Compared to the initial waverider, the volume will be smaller or larger using the traditional methods. With the fixed blunted radius, the volume and aerodynamic performance is determined. In this paper, a new bluntness method which is named “mixing material method” is developed. In this new method, a new parameter is introduced based on the traditional two bluntness methods. Under fixed blunted radius, the volume and aerodynamic performance can be changed within a wide range by adjusting the parameter. When the parameter is 0 and 1, the novel blunted method degenerated into the “reducing material method” and “adding material method” respectively. The influence of new parameter on the aerodynamic characteristics and volume are studied by numerical simulation. Results show that the volume, lift and lift-to-drag ratio increases with the increase of the parameter under the fixed blunt radius, but simultaneously, the drag will also increase. Therefore, considering the different requirements of the air-breathing hypersonic aircrafts for the balance of thrust and drag, lift and weight, a suitable bluntness parameter can be selected to achieve a balance. This research can provide reference for hypersonic waverider vehicle design.

Mach 5–3.5 Morphing Waverider Accuracy and Aerodynamic Performance Evaluation

This paper investigates a morphing hypersonic waverider concept and determines the morphing surface accuracy and control requirements required to achieve Mach 5 to Mach 3.5 on-design operation. Hypersonic waveriders are of interest in the aerospace community due to their significant aerodynamic performance improvements over conventional vehicles in the hypersonic flight regime, although designed for only a single, specific Mach number. The Naval Research Laboratory (NRL) morphing waverider achieves on-design waverider performance across a range of speeds by maintaining shock attachment through morphing the waverider’s lower stream surface and maintaining a rigid leading edge and top surface. A Q-DEIM sensitivity analysis is performed to define a set of actuator locations on the lower surface, which ensures that the morphing error, defined by the difference between the morphed surface and the desired surface shape, is minimized. This paper demonstrates 5- and 14-control-point cases that reduce 87% and 95% of the morphing error, respectively, for a 2-in.-wide morphing hypersonic waverider designed for wind tunnel testing across Mach numbers ranging from Mach 5 to Mach 3.5. Viscous computational fluid dynamics is used to determine the calculated morphing-error effect on the resulting aerodynamics. The results demonstrate that the 14- and 5-control-point cases achieve 97% and 95% of the performance benefits relative to the on-design waverider stream surface.

Inverse design methodology of cone-derived waverider based on pre-defined shock wave under strong geometric constraints

An inverse design methodology on a waverider is proposed under strong geometric constraints on the basis of the generation method of an arbitrarily-shaped shock wave to obtain an improved performance. First, the generation method of the body contour that can form an arbitrarily-shaped shock wave is introduced in detail based on the method of characteristics. The effectiveness and accuracy of the generation method are verified through numerical simulation. Second, with the aid of the generation method, an inverse design method on waveriders under strong geometric constraints is presented. The waverider designed by the proposed method can satisfy the geometric constraints completely. Then, the influences of the shock wave shapes on the performance of the waveriders are studied through numerical simulation. In comparison with a traditional cone-derived waverider, the waverider based on the shock wave with convex quality can considerably increase the aerodynamic performance under the current geometric constraints. Conversely, the shock wave with concave quality deteriorates the aerodynamic performance of waveriders. The volumetric efficiency can also be improved with the adoption of the shock wave with concave quality. In conclusion, the numerical simulation result demonstrates that the proposed waverider design method can provide an increased flexibility and meet the different requirements of an actual design of hypersonic vehicles in geometric constraints and aerodynamic performances.

Planform-customized waverider design integrating with vortex effect

The global geometric relationship among the inlet capture curve, flow capture tube and planform contour line in the osculating-cone waverider design is deduced by a differential equation set. Planform-customized waverider is enabled to be constructed based on the geometric relationship. Thus the configuration with satisfactory wide-velocity-range performance is proposed, employing vortex effect to improve subsonic performance and shock effect to improve super/hypersonic performance, respectively. To validate the concept, the double swept waveriders are generated as test cases. Compared with flat plate models, the aerodynamic performance and flow mechanics of the double swept waverider are analyzed under subsonic and hypersonic conditions using computational fluid dynamics (CFD) simulation. CFD results show that the performance of the waverider with reasonable planform is favorable under both subsonic and hypersonic conditions, remedying some deficiencies of traditional waverider. The work demonstrates a new thought for wide-velocity-range configuration design.

Waverider Configuration Design With Variable Shock Angle

A novel waverider design methodology is proposed with a variable shock angle based on the osculating cones' theory. The expected shape with special requirements can be generated by arranging the distribution of shock angle using the new method. Contrast investigation is conducted on three waveriders, which are designed with constant, decreasing and increasing shock angle distribution starting from symmetry plane at the average shock angle of 12°. The feasibility of the proposed approach is validated by the computational fluid dynamics (CFD) simulation. The results show that the distribution of shock angle has a significant influence on the lift-to-drag ratio and volumetric efficiency. Waverider with decreasing shock angle owns the greater volume and volumetric efficiency but with weak aerodynamic performance. The waverider with increasing shock angle has a higher lift-to-drag ratio and enhanced the static stability but with lower volumetric efficiency. The performance of waveriders with variable shock angle under off-design and blunted conditions is also investigated, which reveals a great overall aerodynamic performance and good robustness.

Influence of surface pressure distribution of basic flow field on shape and performance of waverider

This study investigates the influence of the surface pressure distribution of a basic flow field on the shapes and performances of waveriders. First, three axisymmetric basic flow fields having different surface pressure distributions but identical shock waves are designed and obtained using the method of characteristics (MOC). Second, three waveriders—increasing-pressure, constant-pressure, and decreasing-pressure waveriders—are generated from these three basic flow fields. Finally, numerical methods are employed to verify the design procedure of waveriders with different pressure distributions of the basic flow field and to analyze the differences between the three waveriders. The obtained results show that the surface pressure distribution of the basic flow field is an important factor in the design of waveriders. The waverider generated from the basic flow field having increasing surface pressure along the stream direction has a larger volume and lower lift-to-drag ratio. In contrast, the waverider generated from the basic flow field having decreasing surface pressure along the stream direction has a smaller volume and higher lift-to-drag ratio. Changing the surface pressure distribution of the basic flow field can lead to greater flexibility in the design and optimization of hypersonic waverider vehicles.

Modification impact on aerodynamic performance of hypersonic waverider

AbstractWaverider serves as a good candidate for hypersonic vehicles. The typical waverider has sharp leading edge and no control face, which is inappropriate for practical use. This paper puts forward a method modifying the waverider, and the modification impact on the performance of waverider at hypersonic flow conditions is studied. The modification is based on blunted waverider, includes cutting the tip and introducing two control wings. The modification’s effect on aerodynamic performance is obtained and analysed through Computational Fluid Dynamics (CFD) techniques. When blunted with 2cm radius, the waverider retains its good aerodynamic performance and the heat flux at the stagnation point can be managed. Three factors of the introduced wing are argued, the fixed angle, aspect ratio and wing area. Results show that influence on the aerodynamic coefficient is slight and the vehicle retains its high lift-to-drag ratio. The main influences of the modification are the control ability and trim efficiency, which is the motivation of this work and can be adapted when designing a practical waverider.

Bluntness impact on performance of waverider

Waverider serves as a good candidate for hypersonic vehicles, especially for high lift-to-drag ratio aircraft. Restricted by aerodynamic heat and manufacture techniques, the sharp leading edge of waverider needs to be blunted. In order to study the blunt leading edge’s influences on the waverider, computational fluid dynamics tools are used to study the aerodynamic and aero-thermodynamic property of waverider with different blunt radii. The numerical methods are validated by test case and empirical formula. Numerical simulations show that blunting the leading edge could reduce the maximum heat flux effectively, but it also degrades the aerodynamic performances. When the blunt radius increases, the aerodynamic performance degrades significantly, while the heat flux wears off. With a fixed blunt radius, the aerodynamic performance mainly depends on the angle of attack; while the heat flux is less affected by the angle of attack. When designing waverider, the influence of bluntness on aerodynamic force and heat flux should be considered synthetically and the optimal balance point needs to be determined.

Superorbital expansion tube tests of a caret waverider

A computational and experimental study was conducted to assess the potential of testing waverider configurations in a high-performance, short-duration expansion tube facility. The tests were performed in the newly commissioned X3 superorbital expansion tube and provide the first experimental data of a waverider tested at a stagnation enthalpy and equivalent flight speed exceeding 40 MJ/kg and 9 km/s, respectively. Two simple caret configurations were chosen as benchmark test cases to test the use of the facility, instrumentation and numerical models to investigate these flows. The general performance of the sharp and blunt leading edge waveriders at angles of attack ranging from 0 degrees to 5 degrees were analyzed and compared to CFD and theoretical predictions. For the conditions tested, the presence of a strong viscous interaction caused the shock wave to be detached from the leading edge of the models resulting in a significant loss in performance. An analytical model was developed to account for the strong coupling between the shock wave and boundary layer. Results were shown to be in very good agreement with CFD estimates for both configurations at all angles of attack considered. Finite-rate chemistry CFD simulations indicated that real gas effects other than the residual levels of nonequilibrium freestream dissociation present in the expansion tube flow were negligible for the conditions tested. The study also revealed that a past flow visualization technique gave a false indication of the leading edge shock location. An improved experimental visualization technique was successfully tested with results from these tests correlating well with computational estimates. This study successfully demonstrated the use of the facility to study waverider performance at speeds representative of orbital flight.

The effect of conical flowfields on the performance of waveriders at Mach 6

The performance of 23 kinds of waveriders, derived from different conical flowfields, is analyzed by the numerical computation under the conditions of fight speed of Mach 6, attack angle of 0° and flight altitude of 30 km. These results indicate that the performance is influenced by the shapes and the width to height ratios (W/H) of generating cones. The geometrical parameter and the lift coefficient are proportional to W/H, while the drag coefficient and the lift to drag ratio (L/D) have extreme values. Considering the base drag and the computation errors, the waverider with the highest L/D is cut from the elliptical cone’s flowfield (W/H = 1.5–1.618), and the configuration with the lowest drag can also be obtained at W/H = 1:1.5. Accordingly, good suggestions are proposed for practical design based on these computational results.

Aerodynamic characteristics of a hypersonic viscous optimized waverider at high altitudes

The present paper addresses the applicability of the basic concept of waveriding at high altitudes, and the extent to which the large viscous forces degrade the aerodynamic performance of waveriders. The waverider under consideration was designed using a continuum flow methodology. It is shown that the lift-to-drag ratio of high-altitude/high-Knudsen-number waveriders can be expected to be significantly lower than their low altitude/low Knudsen number counterparts. The aerodynamic performance of a representative waverider which was optimized for a 90-km, Mach-25 application is studied for altitudes ranging from 97 km to 145 km and incidence angles of 0 to 30 deg. Typical values of the lift-to-drag ratio were computed to be in the range of 0 to 0.3. Friction forces are mostly responsible for this poor performance. Friction forces account for more than 93 percent of the drag and significantly reduce lift.