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Waverider has high lift to drag ratio and will be an idea aerodynamic configuration for hypersonic vehicles. But a structure permitting aerodynamic like waverider is still difficult to generate under airframe’s geometric constrains using traditional waverider design methods. And furthermore, traditional waverider’s aerodynamic compression ability cannot be easily adjusted to satisfy the inlet entrance requirements for hypersonic air-breathing vehicles. The purpose of this paper is to present a new method named osculating general curved cone (OCC) method aimed to improve the shortcomings of traditional waveriders.

A basic curved cone is, first, designed by the method of characteristics. Then the waverider’s inlet captured curve and front captured tube are defined in the waverider’s exit plane. Osculating planes are generated along the inlet captured curve and the designed curved cone is transformed to the osculating planes. Streamlines are traced in the transformed curved cone flow field. Combining all streamlines which have been obtained, OCC waverider’s compression surface is generated. Waverider’s upper surface uses the free stream surface.

It is found that OCC waverider has good volumetric characteristics and good flow compression abilities compared with the traditional osculating cone (OC) waverider. The volume of OCC waverider is 25 per cent larger than OC waverider at the same design condition. Furthermore, OCC waverider can compress incoming flow to required flow conditions with high total pressure recovery in the waverider’s exit plane. The flow uniformity in the waverider exit plane is quite well.

The analyzed results show that the OCC waverider can be a practical high performance airframe/forebody for hypersonic vehicles. Furthermore, this novel waverider design method can be used to design a structure permitting aerodynamic like waverider for a practical hypersonic vehicle.

The paper puts forward a novel waverider design method which can improve the waverider’s volumetric characteristics and compression abilities compared with the traditional waverider design methods. This novel design approach can extend the waverider’s applications for designing hypersonic vehicles.

Audit firm diversification can take many forms. Strategic management theory suggests that if the diversification has a narrow focus, it can have a positive effect on performance through knowledge spillover. However, if the diversification is too wide, the lack of economies of scope may cause an even negative impact on performance. The purpose of this paper is to examine the effect of an audit firm’s diversification strategy on audit quality.

Specifically, the authors test whether auditors can benefit from knowledge spillover in their area of specialization.

The authors find that the magnitude of discretionary accruals and the balance of below-the-line item are significant lower for clients from narrowly diversified area than those from a widely diversified area, suggesting a higher audit quality due to possible knowledge spillover. In addition, the authors find such benefits are more pronounced with clients with high earnings volatility.

This study extends the studies on auditor industry specialization by examining the effect of audit firms’ diversification on audit quality and assessing potential differences on audit quality between narrow and wide diversification.