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Objectives: To present a new solution to the field equations obtained for Bianchi type-III universe by using the law of variation of H, which yields constant DP. Methods: We study a Bianchi type-III cosmological model with a cloud strings with particles connected to them in Lyra geometry. To find the exact solutions of survival field equations we consider here that the shear scalar and scalar expansion are proportional to each other (σ αθ ) that leads to the equation b = c m and secondly we adopt the assumption considering the Deceleration Parameter q as a negative constant quantity giving the inflationary model. The geometrical and physical properties are studied and compared with the recent observational data. Findings: The present model starts at t=0 with 0 volume and as time progresses it expands with accelerated rate and the model shows that the present universe is particle dominated.

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Here we studied Bianchi type-I cosmological models with massive strings in general relativity in five dimensional space time. Out of the two different cases obtained here, one case leads to a five dimensional Bianchi type-I string cosmological model in general relativity while the other yields the vacuum Universe in general relativity in five dimensional space time. The physical and geometrical properties of the model Universe are studied and compared with the present day’s observational findings. It is observed that our model is anisotropic, expanding, shearing, and decelerates at an early stage and then accelerates at a later time. The model expands along x, y, and z axes and the extra dimension contracts and becomes unobservable at t → ∞. We also observed that the sum of the energy density (ρ) and the string tension density (λ) vanishes (ρ + λ = 0).

Here we studied Bianchi type-III string cosmological models generated by means of a cloud of strings with particles connected to them in the framework of Lyra geometry considering five-dimensional space-time. To obtain the exact solutions of field equations we consider that the shear scalar and the scalar expansion are proportional, σ∞θ which leads to D=cn and secondly we adopt the assumption considering the Reddy String Condition, ρ+λ=0. From the two different cases obtained here, first case leads to the Bianchi type-III string cosmological model in Lyra geometry in five-dimensional space-time and the second case leads to the five-dimensional vacuum universe in general relativity. The Geometrical and physical properties of the model universe are studied comparing with the present day’s observational findings. The model universe obtained here starts with the big bang and as time progresses both particle density ρp and energy density ρ decreases with expansion of our Universe.