<p>Blended Wing Body (BWB), a conceptual aircraft developed in recent times, could certainly be a revolutionary design with dynamic qualities such as increased passenger capacity, lower noise, and better fuel efficiency. Detailed aerodynamic investigations of such conceptual models in various flow regimes and under different parametric variations are essential to achieve the above-mentioned qualities. The present investigations have been carried out by adopting experimental and computational paths to obtain the effect of dihedral and anhedral angles on the wings of a Blended Wing Body configuration. The experiment was conducted inside an open circuit wind tunnel with a contraction ratio of 9:1. The dihedral/anhedral angles had minimal effect on some aerodynamic characteristics of the configuration studied. However, the flow over the wings was observed to be affected as the dihedral was implemented. The flow seemed to have been strongly affected at higher angles of attack due to anhedral and dihedral angles. Highly complicated flow was observed on the wings due to and complexity of vortical structures. Interestingly, the variation in the lift and drag coefficient with change in the dihedral angles was found to be a function of the cosine of the dihedral angle and the force coefficients for a zero dihedral/anhedral angle (Φ = 0°). This finding significantly provides a mathematical relationship that can be used to predict the aerodynamic behavior of BWB configurations. Additionally, Z-wall shear analysis at x/c = 0.85 location shows a 10–12% inward shift in zero-shear locations (flow separation onset) for dihedral wings versus the baseline configuration. A reasonable agreement between experiments and computations was also observed, further validating the findings of this study. </p>

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Effect of anhedral/dihedral wing angles on a blended wing body at low speeds

  • Shuvendra Mohan,
  • Priyank Kumar

摘要

Blended Wing Body (BWB), a conceptual aircraft developed in recent times, could certainly be a revolutionary design with dynamic qualities such as increased passenger capacity, lower noise, and better fuel efficiency. Detailed aerodynamic investigations of such conceptual models in various flow regimes and under different parametric variations are essential to achieve the above-mentioned qualities. The present investigations have been carried out by adopting experimental and computational paths to obtain the effect of dihedral and anhedral angles on the wings of a Blended Wing Body configuration. The experiment was conducted inside an open circuit wind tunnel with a contraction ratio of 9:1. The dihedral/anhedral angles had minimal effect on some aerodynamic characteristics of the configuration studied. However, the flow over the wings was observed to be affected as the dihedral was implemented. The flow seemed to have been strongly affected at higher angles of attack due to anhedral and dihedral angles. Highly complicated flow was observed on the wings due to and complexity of vortical structures. Interestingly, the variation in the lift and drag coefficient with change in the dihedral angles was found to be a function of the cosine of the dihedral angle and the force coefficients for a zero dihedral/anhedral angle (Φ = 0°). This finding significantly provides a mathematical relationship that can be used to predict the aerodynamic behavior of BWB configurations. Additionally, Z-wall shear analysis at x/c = 0.85 location shows a 10–12% inward shift in zero-shear locations (flow separation onset) for dihedral wings versus the baseline configuration. A reasonable agreement between experiments and computations was also observed, further validating the findings of this study.